Free tool
What calibre is this?
Measure the movement, type the numbers in, and see which Omega calibres fit. Every specification here is transcribed from Omega's own GF 620 spare-parts catalogues — 176 calibres in all.
Fill in what you can — every field is optional, and more fields means fewer candidates.
Measure before you buy anything on the strength of this. These are the figures Omega printed, and a movement that has been serviced, re-cased or made up from parts may not match them. We get it right most of the time — but back your purchase with your own measurement, and if you find us wrong, tell us and we'll correct the record and say so.
How to measure it
Diameter is across the main plate, not the case — Omega quote it in millimetres, and the old catalogues sometimes give it in lignes instead (1″′ = 2.2558 mm, so a 12″′ movement is 27.07 mm). Height is the movement's own thickness, without the dial or hands. Jewels are usually printed on the bridge or the plate along with the calibre number, and counting them by eye is unreliable — read the marking if it's legible.
If the calibre number itself is legible, type it into the last box. That's the reliable route; the measurements are for when the marking has been polished away, which after sixty years it frequently has.
Narrowed it to two and can't tell them apart? That's the common case, and it's what the written report is for — send six photographs and I'll settle it against the catalogue folios and put it in writing. What US$75 buys.
Watch Breaker is an independent identification specialist and parts dealer and is not affiliated with, endorsed by or connected to Omega SA or the Swatch Group. Omega is a trademark of Omega SA. Specifications are transcribed from printed catalogues and may contain transcription errors; corrections are welcome and published. Terms.