Serial number
Engraved on the caseback. Required.
Free watch tools
Watch production year checker
Enter the serial number from your caseback to estimate when your Seiko or Citizen was made.
Free
No sign-up
Instant result
Choose your brand
What you'll need
Calibre or movement
The first four characters. Optional — narrows the decade.
Approximate era
Purchase date or model generation. Optional — resolves repeating years.
Questions
Does a serial number prove a watch is authentic?
No. Casebacks and movements can be replaced, so a valid serial isn't proof of authenticity.
Why do I get more than one possible year?
Both systems encode only the last digit of the year, so it repeats every decade. Add the calibre or an approximate era to narrow it.
Is my serial number stored?
No. Everything runs in your browser and nothing is sent to Wrist Bear.