A guide to Omega vintage watch reference codes

Omega replaced their existing 5digit case reference code system in the early 1960s with a new one which was used to identify their various case designs.  The code is in the format XXX.XXX(X) and the 3 digit prefix denotes details about the case design, whether it’s a gents/ ladies, waterproof or not and the type of movement it houses, manual or automatic.  The  3 or 4 digit suffix denoted the actual model number.  This is not to be confused with the watch serial number which is stamped on the movement itself or on the rear cover or lug on later watches (c. 1998 onwards).

The table below denotes the codes for the 3 digit prefix.  A Speedmaster Professional for example, would carry the code 145.0022 (1- gents watch/4- manual wind chronograph/5- Water resistant).

1st Digit


2nd Digit


3rd Digit


1 – Gent’s Watch 1 – Manual winding without second 1 – Non-water-resistant
2 – Gent’s Jewellery Watch 2 – Manual winding small second 2 – Non-water-resistant Calender
3 – Gent’s Bracelet Watch 3 – Manual winding centre second 3 – Non-water-resistant chronometer
4 – Gent’s Jewellery Bracelet Watch 4 – Manual winding chronograph 4 – Non-water-resistant chronometer calender
5 – Lady’s Watch 5 – Self-winding without second 5 – Water-resistant
6 – Lady’s Jewellery Watch 6 – Self-winding centre second 6 – Water-resistant Calender
7 – Lady’s Bracelet Watch 7 – Self-winding chronograph 7 – Water-resistant chronometer
8 – Lady’s Jewellery Bracelet Watch 8 – Electronic chronograph 8 – Water-resistant chronometer calender
9 – Electronic

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  1. hedley roberts says

    help,could you shed any light on my omega that i bought recently and had restored(watchmaker said it was the best he had seen for a long while)and my jeweller friend said the jewels are top rate.
    the watch is a bumper automatic,chronometer but uncertified?
    the serial number is 10912521 which would date it to 1946/7,
    the number inside the back case is 2757-9sc the external rim of the back case has seamaster to the top and waterproof to the bottom,
    there is no calibration stamped on the movement,
    under the balance wheel is stamped 28-10 ra,
    no seamaster name to the dial,
    any information would be grateful,regards hedley.

    • says

      Hi Hedley, First of all Omega watch jewels have no value and are made synthetically, they aren’t rated for quality like natural stones. Some watches will have gold settings but Omega didn’t use this technique in wristwatch movements. Calibre 28.10 was Omega’s first bumper model. I believe there was a chronometer rated version but this would be designated on the rotor as being adjusted for 5 positions indicating the positional testing required for chronometer certification. The Omega database lists CK2757 as being a Seamaster case first seen in 1953 which creates an anomaly with the movement serial number but I suspect that this case number was also used previously in cal. 28.10 movements. The first Seamaster models appeared around 1948. I would guess your watch dates from 1949.

  2. Tim says


    As far as I am aware, the 3/4 digit number was a three digit number originally, and an extra ‘zero’ was added as a prefix to indicate recently remanufactured parts. So if my original Speedmaster was a 145.022, a newly manufactured replacement caseback would be labelled 145.0022. Similarly a 1960s Seamster 300 was denoted 166.024, but my brand-new remanufactured case (2010 vintage) is stamped 166.0024 inside the screw-on back.
    Unfortunately I am not sure when this extra zero was added; perhaps Omega can help?

  3. Tim says

    Hi, I think we are almost on the same wavelength. In modern Omega literature (websites) I have seen only 0xxx – I have not seen much original paperwork from the 1960s/70s so I do not know if there were any 0xxx references then, but I will take your word for it; certainly all the older models I have seen have the three-digit codes, and all the new replacement casebacks I have seen have only had the four-digit codes … but as I am not a watchmaker I have only seen a few of them!

    • says

      If you take a look at the image of the Chronostop movement and caseback at the top of this page you will see the ref. 146.010 which is listed as 146.0010 in the Omega database. Also be very wary of replacement casebacks especially for the 1960s Seamaster 300 as there are many fakes around which have been recently manufactured in Eastern Europe.

  4. Earl says


    I had the back cover of my speedmaster reduced opened and saw two reference numbers.175 0032 and 175 0033.

    I believe my watch is 175 0032 as it is stainless steel and does not have any gold on it. can you help me on this? Has my back cover been replaced?

    Thank you.

  5. matthew says


    I inherited a watch 15 years ago which purports to be an Omega, the movement number is 8795247 and is a 15 jewel movement. It is in a hallmarked gold case (possibly ladies as quite small). The case is a dennison with number 96578. The face is ivory coloured with roman numerals and a separate second hand dial at the bottom of the dial (where 6 would be). I do not believe it is on original bracelet as is on a stainless steel and gold expanding band marked excalibur 860662 model 49.

    Any information would be nice as I have been unable to find a matching image of the watch on the web.

    • says

      Hi Matthew. You have all the information right there. The only thing missing is the movement calibre number which will be stamped under the balance wheel. Check the assaying office and date of the hallmark and see if it ties up with the date of the serial on the movement. 8795247 dates to circa 1938.

  6. Michael Dovey says

    I have possession of my late brother-in-law’s watch. It is a beautiful timepiece that was given to him as a long service award. It is not working and I doubt it has been serviced. I am keen to get it going and used on a daily basis, it doesn’t deserve to be put in a drawer as a keepsake. I have been quoted £350 by an Omega dealer for a comprehensive overhaul, including new glass etc. I thought it was a wind up watch but the technician says it is automatic, which would be the clincher for me to get it fixed even though I realise I could get a perfectly good watch from Argos that would keep better time. NOT THE POINT THOUGH. In memory of my brother-in-law I want it back in circulation and on my wrist and that of my son one day. Can you give me some detail about the watch. I still have the original paperwork; It reads -Metal ref GOLD BL1325017 —
    Mov. No 35786601

  7. Fawad Tayyab says

    Dear Mr. Robin Armstrong,
    I hope this note finds you well.
    I came across your website today, I’m actually considering to buy a pre-owned Omega Seamaster from a very famous website (through a dealer), but I’m a little confused about the authenticity of the watch. The inside of the back cover says “LL” as the metal code, was that really one of the codes? The watch is a Seamaster Quick Date and its inside back case mentions this number: 1660118. Plus, the outside of the back case does not carry the seamaster sign (you know the dragon sort of sign). The serial number is 36443482. Is this watch real in your opinion? Did Omega ever make a seamaster without a seamaster sign on the back cover?….I’ll be very thankful for your advice.

    Kind regards,
    Fawad Tayyab

    • says

      Omega case code 166.0118 is from an Omega Geneve and should house a calibre 1481 automatic movement. The case should be a barrel shape with very short bevelled lugs. I’ve never seen this configuration in Seamaster form and would think this is unlikely to be genuine Seamaster.

  8. Phil says

    Hi Robin
    The article is very interesting, I was wondering if you have any information on the pre-’63 five digit number scheme. In particular i’m interested in case ref 14389 which I can’t find in the Omega heritage database. I came across a Seamaster 30 cal 269 at a local antiques market in this case. An internet search has uncovered a variety of Seamasters using this case – a few exmples are identical to the one I’ve seen (linen dial, sub second, with Omega, Seamaster, 30 under the ’12’) but many others without the ’30’ on the dial or with cal 268 movements. Were these cases used for a variety of watches

  9. Mark says

    Hi. I have a speedmaster professional mkii I bought 5 years ago but the only number I have for it is engraved on the back of the case which reads 17/8770. Could you shed any light on this as I want to get it serviced but want to make sure it’s right first.

        • says

          It’s likely to be watchmakers service mark if it has been scratched in by hand. Serial numbers are properly stamped in to movement or the case on later models. Any visible numerals on the bracelet or strap have nothing to do with the identification of the watch itself for obvious reasons.

  10. Laurel Heritage says

    Where can I send you pics of a vintage Omega I have. I would dearly love to know how to find information on this watch.

    • says

      Omega reference/model numbers are stamped on the inside of the case back, unless it is an import watch with a case made in the country of sale. Read the article above for details on the numbering system.

  11. Donald Brunke says

    I have a Mens Seamaster automatic day date watch with movement #251715 , it has a number 40 over top of this number . It is a 1022 cal and 23 jewels. Would you have an idea of the year it was made ? Thanks

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