A Brief Overview of Watch Serial Numbers

Serial numbers have been a standard part of a watch since the late 1800s. Although extremely old watches may be marked with the name of a guild or artisan–if at all–serial numbers are now expected on any luxury watch. Some say that the Waltham Watch Company spurred this trend in the mid-1800s, as they brought the assembly line and interchangeable parts to the watch industry. For decades now, watch enthusiasts have looked at a watch’s serial number as a “source of truth” about a watch’s age.

As more watch owners collectively share their information online, more precise inferences can be made about the rarity of various pieces, too. For the most popular watch brands, an online community of collectors has established some sort of serial number chart that can help determine a watch’s age. For other brands, however–like Franck Muller–there is no definitive enthusiast-endorsed serial number chart yet. We’ll go over the basics of watch serial numbers and where to find them.

Where is the serial number on a watch?

On a Rolex watch made before 2012, the registration numbers are engraved onto the watch case, between the lugs. You find the model reference number at twelve, and the serial number at six. The Rolex rehaut is where you’ll find the serial number on newer models, set between the glass and the dial.

In vintage watches especially, the reference number can be found inside the back of the watch-case, a placement that is also preferred by many watch manufacturers, such as Patek Philippe, Jaeger-LeCoultre, and Omega.

Other ones such as Cartier, Officine Panerai, and Frank Muller engrave their serial and model reference numbers externally on the back of the watch case. The serial number of the watch can also be found within the mechanism of the timepiece itself, inscribed onto the movement, generally in the upper part of the bridge.

Should the serial on the movement match the serial on the watch itself?

It depends on the brand. In Rolex’s case, no. With some other high-end brands, yes.

Does the Numbering Mean a Watch is Real?

No, lots of fakes have fake serials and other engravings too. Often, however, they reuse the same numbers. So for instance, beware of any Franck Muller labeled as “77 of 750” because lots of fake ones seem to say that.

What is a Watch Reference Number?

A watch’s reference is different than its serial number; the watch reference number designates the particular model of watch. For example, the reference number of the Hulk Submariner is 116610 LV. Every Hulk has that same reference, while each watch’s serial number is unique.

“Model number” is the same thing as “reference number.” See the Rolex 16750 above, with the model number between the top lugs and the serial number between the bottom lugs.

Replacement Case Serial Numbers

In some instances, watch cases need to be replaced due to irreparable damage. Damaged cases can threaten a watch’s water resistance or even its functioning in extreme cases. But if the serial number is inscribed on the case, what number will be written on the replacement? Well, that depends on the manufacturer.

Apparently, Omega will provide a replacement case with the watch’s original serial number. Rolex, on the other hand, prefers to make their service cases identifiable by a serial number starting with “44” or, more recently, “47.” Every Rolex with a 44- or 47- serial has a service replacement case. Service cases are completely fine from a functional standpoint, but they do negatively affect resale value.

Watches Made with No Serial number?

While having a serial number is an industry standard for watches at this point, there are exceptions. F.P. Journe announced the discontinuation of their Sonnerie Souveraine in 2018, and in an email to customers they noted that “No serial numbers are engraved, as each Sonnerie Souveraine is baptised with its owner’s name.” But those exceptions are rare–collectors should almost always expect to see a serial number on a high-end watch.

“Ghost Serials” and Worn-Off Serial Numbers

Sometimes you might find some otherwise perfectly-original watches with their serial numbers carefully removed from every place. You might hear these called “ghost serials.” The usual explanation is that the watches are stolen, and are rendered untraceable to their original owners this way. While watches with suspiciously erased serial numbers should generally be avoided, keep in mind that there can be a legitimate explanation for worn-off serials. It’s not uncommon for a 70-year-old Rolex to have illegible case markings, for example–over a period of decades, leather straps or even ill-fitting end links can wear away at the numbers etched between the lugs.

Do serial numbers get re-used?

Generally, no, serial numbers do not get re-used by any given manufacturer. It is typical for a watch’s serial number to be unique within that watch brand. However, Rolex is an odd exception to this rule.

The Rolex Serial Reset

In 1954, Rolex was approaching serial number 1,000,000. After case number 999,999, Rolex seemed to reset the “odometer” to 100,000 rather than 1,000,000. Perhaps they wanted to save the extra effort of printing an additional digit, but they’ve created a lot of extra effort for us modern watch enthusiasts! The fact that two watches were made (generally 12 years apart, give or take) for each serial in the 100,000-999,999 range causes many sales listings to incorrectly list 1940’s Rolexes as “1950’s” and vice versa.

Why does my serial have letters and numbers?

If your Rolex serial number includes letters and numbers, that’s called a “random” serial and that means your watch is from roughly 2012 or newer. The more anal-retentive among us might note that if a number is random, it’s by definition not really serial, but, well, everyone still calls them serial numbers.

Serial Numbers on the Dial

Some high-end brands, like Breguet and Daniel Roth, prefer to have a (shorter) serial number for each model, rather than a long string of digits unique within the brand. In these cases, the serial number is often under the logo on the dial. When you’re making less than 10,000 of a model (or less than 20 if you’re Daniel Roth) this is an option, but it’s not feasible for more mass-produced brands.

No matter which watch brand you’re a fan of, you’ve probably looked for your serial number at some point. Serializing is a longstanding tradition in the watchmaking industry with no signs of going away.