Understanding Cartier Watch Model Numbers: 6 Reasons it’s Confusing

Cartier has some of the most confusing model numbers in the business. Modern Cartier watches have both their serial numbers and case numbers on the back, and the case number tells you the general model/size but not the exact spec. There’s also a reference number that corresponds to every exact configuration (at least for Cartier watches made in recent times) but that isn’t written on the caseback. Plus, the formats for these numbers have changed over the years, so we put together this guide to understanding Cartier reference numbers.

The Reference Number Isn’t on the Caseback Anymore

For vintage Cartier watches from the 1970s and 1980s, often a 9-digit code is the only number on the caseback, which represents both the reference (the first five digits) and the serial number (the remaining digits). For much of the 1980s and 1990s, Cartier used a six-digit reference number format which was engraved on the caseback along with a separate serial number.

When Cartier started adding a 4-digit case number to their casebacks in the late 1990s, they also created a formal model numbering system where each configuration had its own long reference number (e.g. W7100056). But they’ve actually never engraved these modern reference numbers on their watches.

Case Number is Different Than Reference Number

The 4-digit case number, which has been on every Cartier watch since 2005 or earlier, signifies the model, size and complication. But it’s not the real reference number–the case number doesn’t tell you the material, bracelet or dial color.

For example, the case code 3729 indicates a Calibre de Cartier Diver, but it doesn’t tell you if it’s steel or two-tone, or whether the bezel insert is blue or black, for example. Ref. W7100056, meanwhile, is a specific configuration of Calibre de Cartier Diver which has a black dial and bezel insert.

Some people also call the 4-digit number the “reference number,” which is confusing, but “case code” is more accurate. Though I should note that, in my opinion, “model number” and “reference number” could be correctly understood as interchangeable.

Cartier Serial Numbers Look Similar to Reference Numbers

Without context, it would be easy to confuse a Cartier watch serial number for a reference number. Since about 2010, Cartier serial numbers have been in 123456AB format, whereas before that it was A12345. Cartier watch reference numbers are never in these formats.

True Cartier reference numbers are either all numbers, or they start with a W. Let’s get into how the format has changed over the years.

The Cartier Watch Reference Number Format Has Evolved

Cartier has changed their watch reference number formats a few times in modern history.

Pre-1973: Rare, Serial-Only

Cartier watches from before 1973 are much rarer than newer ones and should be researched on a case-by-case basis. Usually a serial number is all you’ll find on the caseback.

1973-1980s: 9-Digit Reference+Serial

If you see a 9-digit or 10-digit number on a vintage Cartier watch, treat the first five digits as the reference number. The remaining digits represent the serial number, and these serials do in fact seem to be sequential for each particular reference. This 17011 model from the late 1980s says “170110339” on the back, indicating it was the 339th of that model made, for instance.

1980s-1990s: 6-Digit Reference Era

Cartier went through a phase of using 6-digit reference numbers in the 1980s and 1990s. There are also some 7-digit models, just to keep it interesting–like ref. 6057002 which has a solid silver case, for instance. During this era the serial number is written separately above or below the reference number on the caseback, and it some cases the serial is also six digits which is extra confusing.

1996–2014: Transitional Era

Cartier started engraving 4-digit case codes on their watches in about 1996, overlapping somewhat with the six-digit reference number era. For some precious metal references, that four-digit case number might be followed by a space and one more digit (e.g. “1630 2” which you may see written as “1630-2”).

When Cartier started putting the case number on the caseback, they also introduced a new reference number format beginning with a W–but this full reference number is not on the caseback. The case numbers and serial number, however, still are. Without the benefit of the internet or the original papers, I’m not sure how you would know that the 1630-2 model shown above has a full reference number of W1512256.

Looking at these “transitional” Cartier reference numbers with a W plus seven digits, note that the first three indicate the model family. Prefixes like W410 (Drive), W710 (Calibre de Cartier), W800 (Baignoire), W155 (Crash), and W692 (Ballon Bleu) are followed by four more digits which indicate the specific configuration (e.g. W6920071).

Some exceptions have two letters (e.g., WE902 for Tank Louis Cartier), particularly gem-set ones. And I should mention that, oddly, some limited-edition models like the Cartier Santos Ronde Aviator ref. W20038R3 don’t have 4-digit case numbers on their casebacks at all, and they are numbered simply (e.g. “001 out of 150”) rather than given a long serial number.

2009–Present: Modern Four-Letter Alphanumeric W-Format

Cartier started phasing in their current (and more intuitive) reference number system in about 2009, using a 4-letter + 4-number format that still always starts with W.

What Do the Letters Mean?

The “W” at the start of a modern Cartier reference number just means “watch.” The following letter (like the “S” in “WSTA0059”) indicates the material the watch is made of:

2nd Digit of Cartier Reference Number	Material
S	Steel or titanium
G	Gold
J	Jewelry (usually gold+diamonds)
2	Two-tone
H	High horology (often skeletonized, can be any material)
P	Platinum

The two letters after that (WSTA0059) tell you the model family:

3rd and 4th Digits of Cartier Reference Number	Collection
BA	Baignoire
BB	Ballon Bleu
BL	Ballon Blanc
CH	Crash
CL	Clé de Cartier
HY	Hypnose
NM	Drive de Cartier
PA	Pasha de Cartier
PN	Panthère de Cartier
RO	Rotonde
SA	Santos de Cartier
TA	Tank

Lastly, the four digits at the end (WSTA0059) indicate the specific complication, size, dial color and material. If you see a longer reference number that starts with CR, as in CRWSSA0089, don’t worry:

Ignore the Leading “CR” in the Cartier Reference Number

There is no difference between a Cartier CRWSSA0089 and a WSSA0089, for example. They both refer to the same Cartier Santos LM titanium model. “CR” stands for “Cartier Reference” and technically it’s at the start of every modern Cartier watch’s reference number, but collectors essentially ignore it.

Multiple Cartier Reference Numbers for Identical Watches

Just to add extra confusion, sometimes Cartier even uses multiple different reference numbers for the same exact watch. I think it has to do with the region they’re sold in, but I’m not sure. WHRO0023 and WHRO0064 both refer to the same impressive titanium Cartier watch with a double tourbillon and minute repeater, for instance. But that’s a relatively uncommon phenomenon.

Keeping all these things in mind, hopefully you’ll be able to deduce Cartier watch reference numbers (and serial numbers) without minimal headache.