THE SIMPSONS ARCHIVE
FAQS, GUIDES & LISTS
Your Guide to Production Codes

Created by Matt Garvey

First: why?

Why this document? I was sick of people complaining about the apparent gibberish. These include people on the net (alt.tv.simpsons mostly) and people on DVD commentaries ("I have no idea what these codes mean. It's fun not to know stuff!"). If you see one code every once in a while, no pattern may be evident, but on a larger scale, it's pretty clear; this is a resource to illustrate the scheme and show that it's not hard, and also to explain how it fits in with other TV. On that last note, I get a little long-winded and off-topic the further you read, but it's neat, and besides, I was sitting on all this information I wanted to share.

Why use Simpsons production codes? You don't have to use them, but here's why other people do.

  • They're the single best way to refer to an episode uniquely and succinctly. "Season-episode" numberings could refer to production or broadcast seasons and orders, and broadcast orders can vary outside the US. In addition, the codes are not entirely numeric, so there is little chance of confusing them for another numbering scheme. Titles can work, if you know them, but they get translated overseas and often not directly, for example if the title is a pun, and they're not short; much of the time they're little more helpful in describing the plot or a specific scene anyway.
  • Unlike with some other shows, these codes appear onscreen at the end of the credits, so they can be useful for identifying an episode on air or tape archival, if the rest of the episode is unfamiliar.
  • Thinking about episodes in production seasons can help you consider them by executive producers/showrunners and other trends (switch to digital coloring, widescreen/HD, long holdovers like the 3Gs and 4F24). This thinking even helps with topics like the true first episode (at least as far as dismissing 7G02 from contention!).
  • Because of their brevity they're useful for lists and grids, and because of what structure there is, those lists and grids can be interpreted at a glance.
  • Finally, tradition! Outside of Star Trek, The Simpsons is the first show I know of whose fans referred to episodes by numbers and codes. (Futurama is the only other one that springs to mind. For other series, I don't think most people even know the titles; see an episode list for Friends.) It says something about the geeky nature of such people; who else would latch onto the codes at the end of the credits? Wouldn't you like to? Join us, father! It's bliss!

Overview and Simpsons codes

Production codes are those cryptic letter and number combinations you see all over The Simpsons Archive and elsewhere. They are meant for internal numbering and reference (for reasons similar to those I mentioned above), but they're pretty useful to viewers as well. I want to help make them less cryptic, so here is a simple guide to Simpsons production codes and a brief history of their evolution. Please note that nothing here is from official sources and it's all based on my own deductions, supplemented with information from Brian Petersen and episode lists at epguides.com (occasionally tv.com). (Those lists are not entirely in accord with other sources, and are not official either. However, they are very helpful, and you can do some investigation on your own!)

The names are kind of confusing, but "20th Century Fox Television" is the entity I talk about here. I avoid referring to "Fox" because it means so many more things, and often say "20th" or "20thCFT" instead. See here for more and note where the shows listed appear.

Simpsons production codes can be difficult to follow in part because they span three code traditions from 20th Century Fox Television. Further complications arise from extra twists (numerical discontinuity, the 3Gs, etc.). In short, all Simpsons episode codes consist of a single number or letter designating the production season, a characteristic letter or group of letters marking it as The Simpsons (G, F, or ABF), and two digits indicating the episode number within that season. ("7G" isn't really separable; see below.) More explanation follows below. All seasons are listed as production seasons, which do loosely correlate with broadcast seasons.

7G01-13: Season 1
7F01-24: Season 2
8F01-24: Season 3
9F01-22: Season 4
1F01-22: Season 5
2F01-22, 2F31-33: Season 6
3F01-24, 3F31: Season 7
3G01-04: Season 7 special
4F01-24: Season 8
5F01-24: Season 9
AABF01-23: Season 10
BABF01-22: Season 11
...
HABF01-22: Season 17
JABF01-22: Season 18
...

Full list. You can see some order already, and maybe that's all you wanted to know. For the rest, here are some things to keep in mind.

  • The atomic (smallest individually meaningful) units of the codes differ. In all seasons, of course, the last two digits are one unit. Season 1's "7G" cannot be further broken down; however, the "F", "G", or "ABF" of later seasons is meaningful on its own, and the first digit or letter after season 1 is too.
  • The single-letter seasons do not use the season digit to mean the season directly. For 7F to 5F it actually comes (again not directly) from the calendar year the season was produced.
  • For the "ABF" years, the first digit does actually refer to the season number, but by the time the switch was made, there were no single digits left. Thus, A means 10, B means 11, and so on; I is skipped to avoid confusion. O may be too.
  • Even though "ABF" appears along with a fourth letter exclusively, and it might appear that codes went "4, 5, AAB, BAB" with the "F" remaining constant, remember that "ABF" is now the new "F" in signifying the series. Pronunciations like "DAB-F06" (as heard in episode DABF15) aren't really right.

Before I get to the topic on a non-Simpsons scale, some answers to other questions!

OK, so what about the 7G and 3G episodes and the 31-33s?

  • The 7G season, 1989-1990, is from the tail end of a "grab bag" sort of code assignment that I explore below. Sector 7G is named for this random designation, not the other way around. The letter changed to F, I assume, because "7" was going to be 1990-1991's characteristic number.
  • The four 3G episodes were produced by Al Jean and Mike Reiss, somewhat separately, during the seventh (3F) season. Of course, they didn't air until the eighth and ninth season, but ignore that. A little more info is found later. I can't say for sure why they aren't just 3F25-28, or 3F32-35. Some things are bound to remain a mystery.
  • The high-numbered episodes are special in some way. 2F31 (A Star Is Burns, the Critic crossover) and 2F32 ('Round Springfield) are also somewhat separately produced, and 2F33 and 3F31 are clip shows (2F33 in particular may have been extremely short notice). It's somewhat sensible to separate them with a gap in number. Those episodes air way out of numerical sequence too, further indicating that they're a separate breed. Other episodes like this are the 3Gs and 5F23 (The Joy of Sect) and 5F24 (All Singing, All Dancing); I suspect that 5F23-24 would have been given numbers like 31 and 32 if possible.

Can you explain the MG01-MG48 codes for the Ullman shorts or 7F75/7F76 for the music videos?

No. I've never seen them appear anywhere official, but I suspect the MG codes (MG=Matt Groening) are somewhere between official codes and fan-made designations. You'll notice that the airing order is not the code order, so some internal numbering must have been done, perhaps by Klasky-Csupo; remember that they're not actual episodes and don't need 20thCFT codes. However, "MG" may not be official. That's all I know. 7F75 (Do the Bartman) and 7F76 (Deep, Deep Trouble) are probably official but, unlike with episodes themselves, do not appear in the credits of the works. Note that the prefix corresponds to season 2, when these were produced and aired; 75 is a distance away from the rest to keep them separate.

Are there any other magic numbers besides 31-33 and 75-76?

There's a famous one that's not found anywhere in The Simpsons! The number 79 is found with a large degree of regularity to indicate a series pilot, unaired or aired, usually with the same prefix as the first season. I honestly do not know why that number in particular is used, but my guess is because someone picked a high number one time to distinguish it and it stuck. I doubt it's related to the year 1979, for example if that's when it was first used, but I base that only on reluctance to make quick associations. Other numbers such as 99 and 00 occur from time to time. Family Guy used number 6ACX45 to refer to its "100th" episode special clip show, which like our 2F33 is numbered high and aired before any of the others in its production season; compare my note about 5F23-24 above.

Why do old episode capsules use codes like [8[FG]01]? Why brackets at all?

This seems to have come from confusion about how the episodes were being numbered. Remember, they went from 7G to 7F to 8F in the first three seasons, which is confusing if you expect some order but not total randomness. There may have been anticipation that a renumbering would occur, making the 8Fs into 8Gs or something. The notation is used for the 7Gs and 7Fs too, which is actually more confusing because a single reference could mean either of two episodes. The internal brackets, around "FG", may be an application of regular expressions. The outer brackets are not really part of the codes but some people seem to like them to set them apart; I don't use them except in documents I take over that already had them.

Do they have any hexademical meaning?

Didn't you see all the "G"s? Did you even read the questions above? No, they're not hexadecimal, the proliferation of "A", "B", and "F" notwithstanding. All but 17 episodes until season 16 have digits from 0 to F, but it's just a coincidence from sticking with "F" for so many years and getting a low-lettered new code from the transition.

To learn more about the evolution, read below. It's best if I intertwine it with some general history.

General history and the phases of 20thCFT production codes

This is a general history of 20th Century Fox Television prodution codes. Not surprisingly, these are shows for which 20th is the production company, and that is not equivalent to a show airing on the Fox network. It is very helpful that these shows traditionally put the production code in the credits, as not all shows do. A brief comparison to other code-numbering systems is found below.

The charts are organized simply. Since all shows listed used the last two characters to represent an in-season episode number, I omit these and compare only the prefixes. For the most part (excepting odd holdovers particularly from animated shows), a production season corresponds to its airing season, from the fall of one calendar year into the next. Many of the data were given to me by Brian Petersen, influencing the choice of shows listed as well (at least for the 80s and 90s), and I am quite thankful to him. Other information comes from epguides.com and tv.com, and can conflict at times. I would consider the codes as printed in the credits to be the ultimate authority, but of course I do not have most of these. I suspect Brian did cull his notes from the on-screen credits. Pre-80s shows and others noted as such were found by searches on epguides, tv.com, and IMDb. I do believe they are from 20thCFT, but any corrections and additional codes (such as from tapes or DVD releases) are welcome. I must also note that while the main focus and direct knowledge pertains to the 90s and beyond, this sampling is quite useful overall.

60s: 2-digit prefixes (4-digit numbers)

This is a late addition to the document, but I found it useful to include. An IMDb search for shows produced by 20thCFT turned up a number I was unaware of, and out of those, I found these codes. Again, I do not know for sure that every one used a numbering scheme from 20th, but on the other hand none of them overlap and they follow a certain vague consistency. See also here.

The very earliest shows may have used a different scheme; the only example I found was the second season of Broken Arrow (56-58), which was 4-34 to 4-72, for episodes 34 to 72 of the series, and it apparently was their 4th series. After that, we see four-digit numbers, with a two-digit prefix indicating the series/season and the usual in-season episode number after that. For the most part, the second digit tended to remain the same for a series while the first was incremented by year, and even that first digit has a vague correlation to the calendar year. For this period, any separately-numbered pilots are drawn from a special sequence.

The chart below is organized differently from the rest, because there are so many shows that my preferred method of going down by year would not work. Pilots (when known and separate) are listed in full, season prefixes by themselves. A few series have two-parters which did not get separate codes at this time.

59
-60
60
-61
61
-62
62
-63
63
-64
64
-65
65
-66
66
-67
67
-68
68
-69
69
-70
Notes
Adventures in Paradise354555
Five Fingers3303
37
The Many Loves of Dobie Gillis34445464
Hong Kong41
Bus Stop53
Margie57
12 O'Clock High6011
73
8393Codes preceded by TCF-QM
Daniel Boone748494143050
Valentine's Day6010
75
Voyage to the Bottom of the Sea6008
72
829213Pilot also listed as 7001
Batman????17Uses part 1/2/3 notation
Blue Light6026
88
The Loner21Uses -A/B notation
The Long, Hot Summer20
Lost in Space??95??
Felony Squad891929
The Green Hornet98
The Monroes6031
81
The Tammy Grimes Show11
The Time Tunnel6034
96
Custer25Pilot "6045-6050"?
Judd for the Defense6044
18
28Uses -1/2 notation
The Ghost & Mrs. Muir6205
32
52
Journey to the Unknown39
Julia6203
38
48E3 (see below)
Lancer3151
Land of the Giants2447
Nanny and the Professor59E-4, F-4 (see below)
Room 222494 more (see below)
Table 1: All-numeric codes (up to 69-70).

There are a few odd numbering systems I found as well (see also 70s). Peyton Place (64-69) is numbered sequentially, but was a soap opera and not a weekly.

70s and 80s: random letters and numbers

The numbers were not going to hold out forever. Though there are no collisions that I saw, even among the codes I found over half the available prefixes appear. For the 70-71 season, existing and new shows alike would feature a prefix with a letter and number instead. My notes for this period come from my own net research, except for M*A*S*H and Trapper John, M.D..

Starting in 81-82, there was another change; the prefix became number-letter, not letter-number. This, in some form, has been the basis for all the codes since.

A note on hyphenation: codes listed with hyphens between the first and second character are found that way, though other shows listed without may have used them too. I suspect they were inserted to distinguish the character sets, but the juxtaposition of the random digit with the sequential two digits after it makes for an apparent but useless three-digit number, and I wonder if that explains the swap of the order in the 80s, in addition to refreshing the list of existing codes. Note that shows making the transition to a new system tend to hang on to the old hyphenation (Julia perhaps leaving it out in 70-71, if the guides are to be believed, and M*A*S*H and the like leaving it in for odd-looking codes like 1-G01).

I want to consider all of these designations, through the entire decade of the 80s, to be actually random, in the sense that there is no apparent rhyme or reason to their designation, and no correlation from one season to the next. Some of the numbers in the 80s fit into vague bands, but not really in a helpful way. If you thought keeping track of 1F and 3F was hard, you don't want to try to memorize M*A*S*H codes. Note that even in these lists we see a few prefixes that will repeat.

J
u
l
i
a
N
a
n
n
y

a
n
d

t
h
e

P
r
o
f
.
R
o
o
m

2
2
2
A
r
n
i
e
A
n
n
a

a
n
d

t
h
e

K
i
n
g
M
*
A
*
S
*
H
K
a
r
e
n
P
l
a
n
e
t

o
f

t
h
e

A
p
e
s
J
a
m
e
s

a
t

1
5
T
h
e

P
a
p
e
r

C
h
a
s
e
T
r
a
p
p
e
r

J
o
h
n,

M.
D.
H
a
g
e
n
68-696203
38
69-70486221
59
49
70-71E3E-4?-5*E-1
71-72F-4?-2*F-3
72-73?-1*H-901
J2
J-3
73-74?-3*K-4
74-75B-3D-9*B-5
75-76G-5
76-77U-8
77-78Y-1Y-4*
78-79T-4X-910
T-7
79-80S-6A-910
V-4
80-81Z-4Z-5S-401
?-9*
81-821-G1-M
82-839-B8-C*8-B
83-842-V*2-F
84-853-M*3-L
85-864-M*4-J
Table 2: Letter-number codes (70-81) and overlaps in both directions.
*Room 222's episode guides only list codes as 3-digit numbers at this point. Probably the switch to the letter and hyphen made people ignore the letter entirely. This happens elsewhere. If anyone knows them, tell me!
Karen is listed as D-901 and then 902 to 913, probably shorthand.
James at 15 (James at 16) was based on a TV movie the same year, which I have seen a production code of "905" for. I'm not sure if that fits in at all.
Hagen guides list the pilot as S-401 and the rest as 9__ (including a 901). I assume the letter was ignored there too.
The last four seasons of The Paper Chase occur in springs-summers 83 to 86; I filed them this way.
Note also that several pilots have a "910". This could be significant, though I don't see the usefulness of wasting an entire letter-number combination for a single pilot.

Not included in this chart is That's Hollywood (U-3), because I couldn't tell when it actually aired. Some time around 76. Nor is Cade's County (71-72), listed as 1__; I suspect it also suffered from people ignoring the letter when copying the code down. The New Perry Mason (73-74) is found as PA517342 to -56, suggesting perhaps continuation of its earlier radio or TV versions and ownership.

In the 80s, we see the continued randomness, except in a few examples with consistent lettering and sequential numbering. I suspect that a related code was used when possible, especially toward the end of the decade. Codes on the right-hand side in italics are for shows I found with extra digging, and are probably correct and 20th-produced.

M
*
A
*
S
*
H
T
h
e

P
a
p
e
r

C
h
a
s
e
T
r
a
p
p
e
r

J
o
h
n,

M.
D.
T
h
e

F
a
l
l

G
u
y
9

t
o

5
M
a
n
i
m
a
l
C
o
v
e
r

U
p
M
r
.

B
e
l
v
e
d
e
r
e
T
h
e

W
i
z
a
r
d
H
o
o
p
e
r
m
a
n
T
r
a
c
e
y

U
l
l
m
a
n
S
i
s
t
e
r

K
a
t
e
L
A

L
a
w
A
n
y
t
h
i
n
g

b
u
t

L
o
v
e
I
n

L
i
v
i
n
g

C
o
l
o
r
T
h
e

S
i
m
p
s
o
n
s
A
f
t
e
r
M
A
S
H
M
a
s
q
u
e
r
a
d
e
E
m
e
r
a
l
d

P
o
i
n
t

N.
A.
S.
A
u
t
o
m
a
n
C
h
a
r
l
i
e

&

C
o
.
F
a
t
h
e
r
s

a
n
d

S
o
n
s
H
e
a
r
t

o
f

t
h
e

C
i
t
y
L
e
g

W
o
r
k
H
a
v
e

F
a
i
t
h
A
l
i
e
n

N
a
t
i
o
n
81-821-G1-M1-E1U
82-839-B8-C*8-B7-B2C
83-842-V*2-F2-G1S3-D01
2-L*
2E2J2K2-M
84-853-M*3-L2-Z3J3T 2W
85-864-M*4-J4-E4G 6S6U
86-874V5A4P4W*4L 4S
87-884X5M5J5W*5K 5G
88-895V6X""*7A5Y 5R
89-906V7W5Z7D6Y7H7G 6W
Table 3: Random number-letter codes (81-90), no overlaps.
*The Paper Chase: see above.
The Manimal pilot is 3-D01. It's 90 minutes, but aired just before the rest of the series; I have no good guesses.
The Tracey Ullman Show is kind of odd; the 4W and 5W seasons, as marked, correspond to the calendar seasons they began, but two production seasons were stretched into three air seasons, and 7W is the third production season and 4th year/air season. The numbering might reflect an attempt to keep order by skipping an unproduced 6W season.

90s: some order (table below)

Finally, by the 90-91 season, we see an across-the-board attempt to standardize codes. The digit-letter prefix is still used, but now each digit represents a split calendar year for the broadcast season, and each letter represents one series consistently. Many shows were assigned new letters separate from the 89-90 season, even if they'd kept a letter for a while, to avoid conflicts with older, cancelled shows or existing, conflictingly-numbered seasons of their own. I don't know why 90-91 uses 7 of all numbers, but it probably doesn't matter. 0 is skipped and so 9 leads to 1. A few years down the line, some codes do get reused (I have a list of a dozen or two, including notably 2F, 4E, 4X), perhaps because the old shows no longer mattered, or perhaps in spite of the confusion just to keep consistency. (The Simpsons' special 3G episodes use the correct "3" digit for the time they were produced, and I imagine "G" is used both for its proximity to "F" as well as because of the precedent of 7G.)

So now there is some consistency for shows in this period. Except for seasons before the 90s, the codes are easy to learn, keep straight, and anticipate. The first digit only identifies the year, not the show's own season, but knowledge of the show's premiere date assists with making that connection. (Shows begun in fall 93, like The X-Files, do also happen to match season number to that digit.)

"21st Century Fox": the newest system

However, by the end of the 90s, a problem arises. There will be a "6" year soon, and after that, another "7"? Letters can be changed, but only so many times. Time to devise an entirely new system! This system, which is the current one, replaces the single-letter series identifier with a 3-letter one, and the first digit changes in significance to represent the show's season number. This change is notable, in that the gain of identifying season number does come at the expense of tying it to a calendar year. The sequence of the 3-letter series identifier helps a little (see below). I am not making any judgment on the swap, just mentioning what it entails. (It does, however, help mask discontinuities; Futurama and Family Guy are good examples of this, and 24 skips a year while keeping continuous numbering.) We're only now getting close to rolling the first letter over to "B"; this system should be good well through our lifetimes without any repeats.

Existing, continuing shows would have to make a change in production code style. The general method is to add the current letter after "AB", so for The Simpsons, ABF. New shows from then on would use "AC_" and so forth. I assume "AA" was skipped to avoid confusion and have not seen any shows with that designation. I also see no evidence that new shows got an unused "AB" code (ugh, found some, see below) or existing ones bled over into "AC" territory. Of course, a decision for how to deal with shows past season 9 had to be made very quickly, and Simpsons season 10 used an "A"; although this was not technically the first season to make use of the new format (see below), it was certainly the first most fans saw it on, and I think the simultaneous change added to the confusion.

The specific changeover is a little blurry, however. Not all shows converted at the same time, and some even changed in the middle of a season or used both old- and new-style codes in different places. Footnotes follow in the table below, but since we know a little more about The Simpsons, I will mention this now: According to Brian Petersen and his sources, production season 9 used 5F and 9ABF in different places; "9ABFxx numbers began appearing on all the internal documentation like music cue sheets right away." 5F codes appear in the credits and seem most official; Brian speculates that it's "maybe because when all their scripts were originally written and printed, the 5F## numbers still hadn't yet been 'recalled' by 20thCFT yet" and notes that the first episode pinned with the alternate designation was 5F05 (9ABF05).

The table below encompasses both changes, with three styles of code assignment. Pay attention to the first standardization; many letters that had to be reassigned can be found in this table or the previous one. Other shows, suggested by my information from Brian, do not cross either boundary, but are included to illustrate the consistency (see also below). Note the reuse of letters such as S and E in close proximity. Finally, note the less uniform timing and overlaps of the changes to the 3-letter system.

L
A

L
a
w
A
n
y
t
h
i
n
g

b
u
t

L
o
v
e
I
n

L
i
v
i
n
g

C
o
l
o
r
T
h
e

S
i
m
p
s
o
n
s
G
o
o
d

G
r
i
e
f
P
i
c
k
e
t

F
e
n
c
e
s
S
o
u
t
h

C
e
n
t
r
a
l
S
p
a
c
e
:

A
b
o
v
e

a
n
d

B
e
y
o
n
d
T
h
e

P
r
e
s
t
o
n

E
p
i
s
o
d
e
s
P
a
u
l
y
T
h
e

X
-
F
i
l
e
s
C
h
i
c
a
g
o

H
o
p
e
M
i
l
l
e
n
n
i
u
m
K
i
n
g

o
f

t
h
e

H
i
l
l
B
u
f
f
y
.
.
.
P
i
z
z
a

P
l
a
c
e
T
h
e

P
r
a
c
t
i
c
e
D
h
a
r
m
a

a
n
d

G
r
e
g
A
l
l
y

M
c
B
e
a
l
T
h
e

P
r
e
t
e
n
d
e
r
86-874L
87-885K
88-897A5Y
89-907D6Y7H7G
90-917L7X7U7F7Y
91-928L8X8U8F
92-939L9U9F9K
93-941L1U*1F1K1S1X
94-952F2K2X2M
95-963F
3G
3K3S3E3X3M
96-974F4P4X4M4C4E4VPR*031
97-985F5X*5M/
4ABM
5C5E5V*5Z/
1ABZ
OWAEAM032
98-99AABF6ABX*5ABM3ABC3ABE3ABB*2ABZ3ABQ2ABD2ABU3ABP
99-00BABF7ABX6ABM4ABE4ABB3ABZ4ABQ3ABD3ABU4ABP
Table 4: Orderly number-letter codes (90-98) and three-letter codes (98+), with overlaps.
*In Living Color's final season is probably 1U. epguides.com has IU, but it is most likely a misreading.
The Practice has a pilot code of P8402. It's kind of weird anyway.
Two Guys, a Girl, and a Pizza Place (Two Guys and a Girl from season 3 onward) uses 5Z for its pilot (5Z79) and 5Z01-5Z09, but switches to the new format midseason, so 1ABZ10 and up. It's possible that the second part of the season was not ordered at the same time as the first, which would explain the odd timing of the switch. (By the way: Brian's notes say "52__" but I expect that was a misreading.)
Similarly, Chicago Hope switches format in the middle of season 4. Brian's notes suggest 5M14 to 4ABM15, but epguides.com has 5M15 to 4ABM16.
The X-Files season 6 seems to use 6ABX officially, but epguides goes with 6X. I am sticking with 6ABX.
Brian says Buffy the Vampire Slayer is alternatively known by 6V for season 3, but the episodes themselves say 3ABB on screen.

Note that some series, especially those below, did have letter changes (the single letter with "AB" at the start was not used).

The shows toward the right of the table above are a little odd, and may not all be 20th-produced, or may have fallen under the new scheme from an alternate type. None of the original codes really fit in with the rest, and the new-scheme letters are all new. (Honestly, I'm not sure which codes are official or appeared in the credits; the AB_ codes may be partially or totally due to the retroactive coding discussed below.) The Practice, in addition to its odd pilot designation and first two seasons, seems to use alternate 3P to 8P codes (instead of 3ABQ to 8ABQ), and Ally McBeal also has alternate 2M to 5M (2ABU to 5ABU); neither alternate practice fits with the established format.

In addition to those, Brian's notes include Civil Wars and NYPD Blue, both of which have two code formats that seem at odds with everything else despite being 20th shows. I will include those in discussions of entirely different systems.

I found a few others myself while poking around, along with the 80s codes in italics above. Again, these come from the net and I can only assume they appeared this way on-screen and are 20th shows. Given how precisely they fit the format, I think they'll be useful to include.

B
a
b
e
s
W
o
r
k
i
n
g

I
t

O
u
t
T
r
u
e

C
o
l
o
r
s
D
r
e
x
e
l
l
'
s

C
l
a
s
s
R
h
y
t
h
m

&

B
l
u
e
s
W
i
l
d

O
a
t
s
C
l
e
g
h
o
r
n
e
!
T
h
e

C
r
e
w
L.
A.

F
i
r
e
f
i
g
h
t
e
r
s
S
e
c
r
e
t

S
e
r
v
i
c
e

G
u
y*
R
e
l
a
t
i
v
i
t
y
T
e
m
p
o
r
a
r
i
l
y

Y
o
u
r
s
N
o
t
h
i
n
g

S
a
c
r
e
d
T
h
e

V
i
s
i
t
o
r
4
1
3

H
o
p
e

S
t
.
90-917E7V7T
91-928T8G
92-939R
93-94
94-952W
95-963L3W*3B
96-974B*4D4H4T
97-985K5R5W
Table 5: Additional orderly number-letter codes (90-98), no overlaps. See table 4.
*Secret Service Guy apparently never aired.
Similarly, the second season of L.A. Firefighters may not have either. They still had codes.
The Crew episode guides list the pilot as 3W79, but the rest with an alternate system. It's 20th though.

Finally, what's the deal with the new codes? In short, they're sequential. "AA_" is skipped entirely, it seems; "AB_" is used for recoding existing shows (mostly); and "AC_" starts new shows under the new system. Of course, there were bound to be exceptions; with some digging I came across "ABK" coding for That's Life (Mar-Apr 98), which overlaps slightly with the end of Nothing Sacred (5K), and "ABR" for Getting Personal (beginning Apr 98 and continuing for 2ABR in 98-99), somewhat at odds but not overlapping with The Visitor (5R). Since these shows began mid-season, I guess 20thCFT was eager to start the new system right away. Compare and contrast with Pizza Place.

I haven't seen the letter "I" in the new codes at all (either in the three-letter show signifier or for the season character under The Simpsons, with one annoying exception), and suspect that "O" is not used either. Aside from that, they don't seem to reset a digit when a new season starts or anything, and a code is doled out to a show as soon as it needs a code (note the comparatively early codes for American Dad and The Cleveland Show, which have a long lead time because they're animated). Therefore, the letters only serve to place shows in relative order, but one middle letter doesn't correspond to one year, as close as that relationship seems to be. Some shows use episode number 79 (etc.) for the pilot, unaired or not, but keep the rest of the code. Here is a partial list of shows using this system, along with the season they first aired. Note again that these are not all shows that aired on Fox; they are produced by 20th. Shows with an asterisk were found by searching by code, not by show; question marks indicate less-than-perfect evidence for the code.

ABK 97-98 That's Life (see above)
ABR 97-98 Getting Personal (see above)
ACG 98-99 Strange World*
ACH 98-99 Holding the Baby
ACU 98-99 Martial Law (see below)
ACV 98-99 Futurama
ACW 98-99 Living in Captivity*
ACX 98-99 Family Guy
ADA 99-00 Roswell*
ADC 99-00 Harsh Realm*
ADD 99-00 Get Real*
ADE 00-01 Dark Angel*
ADG 99-00 Judging Amy*
ADH 99-00 Angel
ADK 99-00 Titus*
ADL 99-00 Then Came You*
ADM 99-00 Stark Raving Mad*
ADU 00-01 Boston Public
AEA 00-01 Kate Brasher*?
AEB 00-01 The Lone Gunmen*
AEF 00-01 Freakylinks*
AEJ 00-01 Yes, Dear
AES 01-02 Reba
AEV 01-02 Greg the Bunny
AEW 01-02 The American Embassy*
AEZ 01-02 UC: Undercover
AFB 01-02 The Education of Max Bickford
AFE 01-02 The Bernie Mac Show*? (appears rarely vs. other styles but fits)
AFF 01-02 24
AFP 01-02 Inside Schwartz*
AFY 01-02 Bob Patterson*
AGE 02-03 Firefly
AGH 02-03 A.U.S.A.* (uses 0AGH01 to refer to unaired version of pilot)
AGK 02-03 Still Standing*
AGL 02-03 Charlie Lawrence* (1AGL00 for first episode)
AGS 02-03 Oliver Beene
AGV 02-03 The Pitts*
AHE 03-04 Miss Match*
AHL 03-04 The Lyon's Den*?
AHM 03-04 Wonderfalls*
AHP 03-04 Tru Calling
AHQ 03-04 The Brotherhood of Poland, New Hampshire*
AHS 03-04 Cracking Up*
AJA 03-04 The Big House
AJD 03-04 Arrested Development
AJE 03-04 North Shore*
AJF 03-04 Married to the Kellys*
AJN 04-05 American Dad
AJQ 04-05 Boston Legal* ("F" instead of "AJQ" in some guides)
AJW 04-05 The Inside*
AJX 04-05 Point Pleasant* (also appears as AIX, so I guess it is confusing!)
AJY 04-05 Quintuplets* (summer 05)
AKC 04-05 Jake in Progress*
AKJ 05-06 Prison Break
AKK 05-06 The Loop*
AKL 05-06 Over There* (summer 05 - some list as ALK)
AKM 04-05 Stacked* (premiered in spring 2005 but fairly early to be considered 05-06)
AKP 05-06 Head Cases*?
AKT 05-06 Kitchen Confidential (I assume the conspicuous "KT" is just a coincidence)
AKY 05-06 Bones*
ALF 05-06 The Unit* (some list wrongly as AFL)
ALH 05-06 How I Met Your Mother* (1ALH00 for pilot)
ALJ 05-06 My Name Is Earl
ALR 05-06 Pepper Dennis*
ALW ----- Misconceptions* (from tv.com, never aired)
AMA 06-07 The Winner*
AMB 06-07 Vanished*?
AMH 06-07 Standoff*
AMK 06-07 Shark*
AMP 06-07 Drive (see below)
AMU 06-07 Wedding Bells* (maybe)
ANJ 07-08 Journeyman*
ANK 06-07 The 1/2 Hour News Hour* (from tv.com)
ANL 07-08 Unhitched*
ANM 07-08 K-Ville* (found only on one forum but seems real)
ANX 07-08 Back to You
ANY 08-09 Life on Mars*
APK 08-09 Dollhouse*
APS 09-10 The Cleveland Show
APT 08-09 Do Not Disturb*
APW 08-09 Lie to Me*

I found some other stuff during my search. You can try yourself. "1ACL01" brings up a fan-made episode guide for 11 seasons of an imaginary spinoff of The Simpsons, The Lovejoys. Apparently it's set for a 2014 premiere, but the author didn't seem to know that the ACL code indicates that the show's been in development since 1998. "1ACP01" turns up two separate fan series. 1ADB01 may be from a show called "Snoops" (99-00); 1AHJ01 may be an unaired show called "Still Life"; and 1AHK01 and 1AHL01 both turn up results for shows that may never have aired.

One exception we've found is Kelsey Grammer Presents: The Sketch Show, a short-lived series in spring 2005, which used the code "VAA" (as in 1VAA01). The "V" seems to designate "variety", perhaps indicating that there are a few special categories. I haven't seen anything else with such a code, and searches for shows with codes "VAB" etc. turn up empty. On the other hand, I do not see tremendous evidence one way or the other on its being a 20th show (information is spotty), even though it did air on Fox.

Rewriting history: backnumbering and alternate styles

There is also some retroactive recoding going on, perhaps for internal reference anyway. Take any show with a 3-letter designation and the numbering is easy. (Simpsons episodes 3G01-04 are now 7ABI01-04. Yeah, really, even with the "I". I don't know if 31-33s are lowered to be contiguous, as I have only seen a few episodes renumbered, but I doubt it, since 79s tend to be OK.) Brian Petersen's list included some new codes for much older shows, such as a "DYO" designation for Dynasty and "YAL" for Hill Street Blues (1DYO01, etc.). These are used on "Fox in Flight" menus and apparently places like AOL Video and iTunes too.

The "Fox in Flight" choices are available online here. Based on the selection in March 2009, I have made these categorizations.

  • Shows using the existing 3-letter codes for all of their episodes are listed that way. This includes a few shows I didn't turn up in my search, Drive (06-07, AMP) and Martial Law (98-99, ACU), both codes matching their premiere years. This accounts for a few dozen shows.
  • Shows that straddled the boundary from the mid-90s styles to the new system back-number the older episodes accordingly (Simpsons season 1 = 1ABF, etc. Remember that the 3Gs are 7ABIs under this style.). This includes all the relevant shows in the table above except Ally McBeal and Two Guys, a Girl, and a Pizza Place, which just aren't on FIF, and also includes NYPD Blue (see below) with code ABY.
  • A few older shows use the same 3-letter format, but with YA_ codes instead. These are Hill Street Blues (80-87, YAL), Remington Steele (82-87, YAM), The Mary Tyler Moore Show (70-77, YAN), and Newhart (82-90, YAU), all of which originally used various numeric 4-digit codes. These four shows, among others, were from MTM Enterprises, now under 20th.
  • A handful of recent shows use a three-letter prefix and then 3-digit season-episode code, though I'm not sure why. The original codes, from what I can tell, are of a variety of styles.
    AAB### 98-02 The Hughleys
    BCF### 06-08 The Riches
    BCI### 07-   Burn Notice
    CAB### 99-06 Malcolm in the Middle
    CAS### 01-06 The Bernie Mac Show (may be offset by 1)
    CBR### 04-06 Living with Fran
    CBW### 05-06 Killer Instinct
    
  • Three older shows with 4-character alphanumeric codes that didn't stretch into the new system tack "TA" or "TB" onto the front. LA Law is TA+code and M*A*S*H is TB+code (see details above). Murder One (95-97) uses TA+code also, though its original codes were ON## and OU##, unlike the usual style. Why TA was repeated (or alternatively why it wasn't used for M*A*S*H, since the codes don't overlap) is not clear to me.
  • Finally, Daniel Boone (64-70), an actual 20thCFT show all the way, which used a variety of 4-digit numbers, ...still uses them. Go figure.

In addition to that, there are alternate ways of using the current codes when the series itself is known. For example, some online TV guides use the 4-character Simpsons codes when available but then switch to (also 4-character) adaptations for the "ABF" years. AABF01 becomes 1001, and so on. Other people may use that format casually; whenever David S. Cohen (what, this is a Simpsons site) cites a Futurama episode, the "ACV" is dropped, so for example "410" for 4ACV10. Some shows (Seinfeld, for example) even use that format natively, though the numbers never appear onscreen. I'm not a huge fan of that, since it leads to possible ambiguity with broadcast-order numbering (Nth episode shown in season M), although I do occasionally use a 3-character shorthand for The Simpsons' later episodes (e.g. B19) because there is no ambiguity.

Non-20thCFT styles for comparison and interest

Other production companies, of course, have different methods. Many are purely numeric and consist of the same room-numbering sort of system: 101 is season 1, episode 1, etc. One that is fascinating to me and easy to find examples of, especially since the codes are in the credits, is anything WB-produced. This includes a lot of ABC (CBS, NBC, CW) shows, but also Fox's Terminator: The Sarah Connor Chronicles. Let's start there; the tone of this section is less chronological and in fact more anecdotal.

The T:TSCC pilot is numbered 276022. No 01, 79, or anything. Note how different it is from other episodes; probably it comes from a separate sequence just for pilots, as we shall see. Production season 1 is 3T6851 to 3T6858, and season 2 is 3T7301 to 3T7322. Kind of a random jump, right? I think codes for all their shows are allotted in 50-episode chunks, without any other structure, from a master sequence. Unused numbers remain that way. Note that this means there is nothing to identify a show by part of its production code, only that seasons from one show or many can be compared to each other for date order. However, series do not maintain the same order within one season. It's marginally more useful than the older (pre-90s) 20th styles. For example, these opening numbers. Pilots are in italics. The chart is not meant to be comprehensive, but I chose shows based on proximity to season 1 of Terminator for illustration. Additionally, I have included ER in this table and the one below, as kind of a link. Believe me, I could poke around for more shows and codes, but you don't want to see it.

Small-
ville
Cold
Case
Nip/
Tuck
One
Tree
Hill
Super-
natu-
ral
New
Adv.
of Old
Chris-
tine
Chuck Push-
ing
Dais-
ies
Big
Bang
Theory
Gossip
Girl
Moon-
Light
Termi-
nator
ER
01-02475165
227601
227251
02-03175051175151
03-04176201475195
176701
176450
176451
177500
177501
176001
04-052T5201??????1776012T5251177851
05-062T6401??????2T59512T6151475285
2T6901
??????2T6051
06-072T77012T79013T50013T57513T5501??????2T7801
07-083T6301????????????3T68013T69013T6701276025
3T6451
276027
3T6501
276023
3T6601
276026
3T6751
??????
3T6951
276022
3T6851
alt #s
08-093T7451????????????3T75513T75013T78513T72513T70513T7351??????3T7301alt #s
Note: Some pilots with a code ending 00 may not be the official numbers, but they're what I turned up. I only watch one of these shows, so the rest of the codes are from epguides.com and other sources. You can note the trends yourself.

As another example, consider some older series. Codes are all culled from online sources, and many may be slightly off, especially when only a few examples exist. These are drawn from 80s-90s shows I knew had such codes, and I pulled up a few more based on proximity to the 91-92 season. It's also worth noting that this tradition and several others, but not recent/modern 20th, use "A" and "B" after the same number to denote two-parters, instead of entirely different numbers. These are the first numbers from each chunk. As before, italics represent pilots, when separate numbers exist and are known.

Per-
fect
Stran-
gers
Full
House
[Guns
of]
Para-
dise
Family
Mat-
ters
Gab-
riel's
Fire
DEA Fresh
Prince
Sis-
ters
Home-
front
Step
by
Step
ER
85-86174901
86-87175501
87-88176501??????
88-89177507
to 526
445227
445228
??????187101
to 112
445463
to 476
89-90445751445851445951445230
446001
90-91446301??????446701446451475034
446601
475035
446651
446801475039
446751
91-92446851446951446901446901*447251447151475049
447001
92-93447951447851447801446951*447651447701447901
93-94??????455351alt #s455851455451
94-95??????456201alt #s456501456351475079
456601
95-96457101alt #s457001457151457201
96-97465301465351465401
97-98466451466501466351
98-99467551
99-00225451
00-01226251
*The Fresh Prince of Bel-Air numbers start like they're in sequence with the rest but season 2 and 3 step on other series' allotted numbers. Its last three seasons are listed online with completely different numbers. I would be surprised if this can truly be classified with the rest.

Note how the sequence from year to year is a little more obvious. In fact, looking at both sample charts, you should be able to spot several things. Key seems to be the idea that in a pinch (running out of a sequence), any batch of 6-digit numbers would do. Not only does the Fresh Prince of Bel-Air system seem to step on others, I see a batch of codes used by both Perfect Strangers and One Tree Hill. If the numbers are correct and did come from the same production company, that's not good. I don't know what prompted the change to numbers starting with 4 in the late 80s, but the 17____s came back early this century and didn't last too long, almost as if they poked around for a few unused ones. Pilot numbering managed to hang in there, didn't it? (Look at the 475___ numbers.) We seem to have gotten into a new era by around 04-05, but what's with the T all of a sudden? I wouldn't be surprised to learn it was a 7 that got misread internally or something.

You can see what keeps me occupied, but enough pondering of that. A brief foray into some other styles I wanted to mention, just to show a bit of sanity and a lot of insanity. You may look these up on epguides.com.

Malcolm in the Middle
This is one of the best systems I've seen, though I am fairly partial to all 20th styles because the letters really help make the codes standalone. Except for the pilot, which is numbered 10012-99-179, differing only in the first number group, and does actually use the magic "79", all episodes are 06-YR-SEE, that is, YR=two-digit year of season's start, S=one-digit season, EE=two-digit episode. I assume "06" is code for the series itself, but as I can't find any other codes of this style*, I can only speculate. The code contains everything though: series identifier, year of broadcast, season number, and of course episode number within that season. Even the best 20th codes miss one of those details. (*Malcolm's production logos include Satin City, Regency Television, and Fox Television Studios. Regency also did Roswell but that uses #ADA## notation. Satin City appears to have produced nothing else but a single "Red Dwarf" show. Fox Television Studios is a child of 20th Century Fox; I notice from my Fox in Flight research that The Hughleys and Burn Notice follow similar formats for their codes but with longer series identifier numbers, and at least the latter is produced by FTS. So perhaps it is a separate system used only by them.)

Duckman
A good example of a small number that must be tied with the series name to make any sense, but has some external logic of its own and then some inconsistency to boot. Every code is four digits. The first digit is 4. The second digit is 0, 2, 3, or 4, where each one corresponds somewhat to a broadcast season, but not entirely: 0 is season 1 (13 episodes), 2 is season 2 and four episodes of season 3 (also the magic number 13), but 3 and 4 split on seasons 3 and 4 even when the episode numbering jumps between them (look at "Aged Heat 2"). Then there are the episode numbers (third and fourth digits), which do not reset every production/broadcast season; they go from 00 (pilot) to 71, but skip 02 and 44 (perhaps to avoid a 4444? perhaps episodes that were dropped during production?). I believe the codes are from Klasky-Csupo, but might be Paramount. Fun to wonder about. See also some of the original codes of older shows with YA_ designations on FIF.

Others from Brian Petersen's notes. They are 20thCFT shows, but may have been part of a different child entity.

Civil Wars
Ran 91-93, apparently used prefixes 0J and 0L onscreen but are listed as 41__ and 42__ elsewhere. The digit 0 never turns up in the other prefixes I discussed, and the timing of the series does not match the freeform assignment of codes like this. Compare:

NYPD Blue
93-05. This also has two simultaneous styles of codes (Brian's, from the screen I assume, are the purely numeric ones). Take a look (season number, codes):

 1: 0K /  51 +two digit episode number
 2: 0V /  52
 3: 0G /  53
 4: 0H /  54
 5: 0T /  55
 6: 0C /  56
 7: 0E /  57
 8: EA /  58
 9: GA /  59
10: HA / 510
11: ?? / 511
12: ?? / 512
As you can see, this show also used the odd 0+letter, assigned somewhat haphazardly, but then letters started filling that place, perhaps after the second character ran out itself. The pure-number approach is easier to understand and now we see how it deals with more than 9 seasons. If these two shows are from the same company, one assumes the "4" and "5" represented each series. Brian says that the show has fallen under the new 20th style and now uses a code "ABY" (as in 1ABY01). I have not seen the codes outside Fox in Flight and other such places. (A two-parter season 9 finale uses A and B after the number in both systems above, but on FIF is listed as one episode with no other designation under this format, 9ABY22.)

The end

That's it. Thanks for reading this far! TV production codes can range from simple sequences that have no meaning outside the context of a series to practically unique designations; 20thCFT has traversed that entire spectrum, in fact, and may be the only company to have done so. It took a quick fix every decade or so, but I find it gratifying that a solution was found. The Simpsons, as I have stated, has been part of three types of code systems from 20th, both a blessing and a curse in understanding, and I hope that by providing some context I helped demystify the character clusters and perhaps even let you remember their meanings for this show as you see them in the future.


Search The Simpsons Archive:    Search Help

[ FAQs, Guides & Lists | Upcoming Episodes | Episode Guide | Capsules | Miscellaneous | Web Links | News | About | Home ]

Last updated on April 16, 2009 by Matt Garvey (garvey@simpsonsarchive.com)