When you have a vintage watch, the question that without a doubt you will keep asking yourself is: when was my watch made? Now, is dating a watch possible? Sometimes it is, sometimes it isn’t. Anyway, it’s very useful as a collector to know how to date a watch.

Serial number

The first thing to check is serial number charts. Sometimes they’re official resources, sometimes they are compiled by brand aficionados. They attempt to combine all the bits of knowledge scattered out there into one, more or less accurate resource.

However, the serial number charts are only available for a handful of manufacturers. Usually for the ones that kept the records properly. That would be Omega, Tissot, Longines, Rolex, and Zenith. If there are official resources, they usually make their way into the Internet and therefore aren’t hard to look up. High-end brands like Patek Philippe or Vacheron Constantin kept (and keep) excellent records, and the serial number tables are available alright.

How to date a watch

Longines 8LN (8.68N) with serial number 7.296.878. That dates it to 1947

Reference number

Some brands are documented well enough to establish a rough date of manufacture by production years of a particular model. Heuer is a good example. OnTheDash, which might just be the best Heuer resource out there, has entire lists of various references of particular model lines, with production years given.

Although Omega is documented well enough to date their watches by serial numbers, the reference numbers can be looked up in the Omega Vintage Database. It’s available on the manufacturer’s website. Even if you know the movement serial, with a researchable reference number you can check if the case, movement, and dial are a match. Obviously, not all of their watches are listed in there but with Omega, that’s as good as it gets.

How to date a watch

Caseback of a Tissot PR516 GL.

Simple date codes

Some brands, like Bulova, used rather simple means of marking the date of manufacture. Bulova used a letter to mark the decade, a number from 0 to 9 to mark the year in the decade.

Rolex sometimes has put the quarter or the month in Roman numerals, and the year in Arabic numerals on the case back.

Omega placed the year of manufacture of a particular batch of cases right after the reference number in Speedmasters.

For Doxa, the first two digits of the case serial number mark the year (only for watches made between  1940 and 1965).

How to date a watch

Codes for Bulova watches

Case markings / hallmarks

It works just fine with gold, silver and platinum British market pieces, cased locally. The markings consist of the purity mark, the sponsor’s/manufacturer’s mark, the assay office stamp, and a “date letter” corresponding to a particular year. Each assay office had its particular style of the “date letters”. As long as you identify the assay office mark, dating a watch is easy, as the British hallmarks are really well documented.

Wrapping up

As you can see, there are quite a few methods for dating a watch. The 2nd article on how to date a watch will contain the following methods:

  • Contact the manufacturer
  • Design
  • Technical features
  • Calibre

Do you have some more tips on how to date a watch ? Please comment below.