Seiko Date Finder


Example #1
6119-8083 | 061187
Mvmt-Case | Serial

"When was my Seiko made?" We hear that a lot here at WatchSleuth so we built this page to help you figure it out. The page includes a calculator along with instructions and example images to help you find the movement caliber, case code and serial number on the back of your watch. The calculator combines the serial pattern with our movement database to suggest possible dates.

Results are possible production dates, not a guaranteed date or an authentication. We use recorded movement-year bounds and the serial-number pattern. Unknown end years do not prove continued production, and some start years are introduction estimates. Family-level searches consider all recorded revisions; include a revision suffix when known.

Seiko Production Date Calculator

Your Results:

Using all recorded revisions of this movement family. Recorded production-year information:

7T62A: start 2002; end unknown.

These are recorded year bounds, not exact manufacturing dates; some start years are introduction estimates.

An end year is unknown. Where a start year is recorded, candidates for that revision extend through the current month, but this is not evidence that the movement remained in production.

The serial number field is blank. Enter it to calculate possible production dates.

Use model-specific history and reliable dated records to narrow the possibilities. A purchase date alone does not prove the manufacturing year because watches can be sold as old stock. The case code is used only to find matching catalog watches, not to narrow these dates. Please send corrections with supporting sources.

You can also view the entire datefinder database. We encourage people to send us additions and corrections.

Matching Watches

The watches below match the movement caliber and case code entered above.

SNA525

SNA526

SNA528


Example #1
6119-8083 | 061187
Mvmt-Case | Serial

Finding the Model and Serial Number


Example #2
6309-576A | 2D5822
Mvmt-Case | Serial

Most Seikos have a "retail" model number that is displayed in the store but not written anywhere on the watch. They also have a "reference" model number that is written on the case back. This reference model number is a combination of two numbers:

movement caliber
case code

These codes commonly have four alphanumeric characters each and are separated by a hyphen. A movement revision may have an additional letter suffix; include it in the movement field if known. In the example images the reference model number is highlighted in red.

The other number you will need is the serial number. This is also on the case back and commonly has six characters, including a letter for some months. We tentatively decode seven-digit serials using the same year/month pattern, but do not claim that interpretation is verified for every historical model. Other formats require separate research. In the example images the serial number is highlighted in blue. Use both the reference and serial numbers when researching your watch.


Example #2
6309-576A | 2D5822
Mvmt-Case | Serial

How is the Date Calculated


Example #3
7S36-03J0 | 411082
Mvmt-Case | Serial

The first digit of the serial number tells you the last digit of the year the watch was made. Looking at the example images:

for example #1 the year ends in 0
for example #2 the year ends in 2
for example #3 the year ends in 4

You may notice this does not tell us which decade. That is why we also ask for the model number. For many movements our database has recorded introduction or production years. Known year bounds help narrow the decade, but a movement family may span many decades. When an end year is unknown, we show candidates through the current month and explicitly flag that continued production has not been established.

These historical examples illustrate why additional evidence matters:

our 6119 records have different bounds for different revisions, so the family code alone cannot settle the decade for #1
our recorded 1976-1987 bounds for 6309 make 1982 a candidate for #2
our 7S36 records start in 1996 and have unknown end years, so #3 can produce multiple candidate decades

The second digit of the serial number is also useful. It tells you the month the watch was manufactured. Here are the possible values:

The remaining digits do not establish the decade, and this calculator does not use them to claim a watch's order of manufacture. Decoding the month in our examples gives:

6119-8083, serial 061187: June in a year ending in 0
6309-576A, serial 2D5822: December in a year ending in 2; 1982 fits our recorded bounds
7S36-03J0, serial 411082: January in a year ending in 4; the serial alone cannot distinguish 2004, 2014 or later matching decades

Example #3 was bought new in 2014, but purchase dates alone do not prove production dates: a watch may have been old stock. Model-specific records and provenance are better evidence.


Example #3
7S36-03J0 | 411082
Mvmt-Case | Serial

Why Do We Ask for the Case Code

If you were paying close attention you may have noticed we asked for the case code in the form above but we did not mention using it when calculating the date. You can leave that field blank and still find the date for your watch however if you complete the field we will provide a listing of watches from our Seiko catalogs that match the movement and case code.

Special Thanks

What you see here is in large part thanks to this excellent Quartzimodo article How to tell when you Seiko watch was made. Unfortunately the Jayhawk Production Date Calculator (by John Gauch) which is linked to in the Quartzimodo article no longer seems to be available, so we built our own. Another useful resource we found during our research was The Seiko Manufacture Date Decoder on the Retro Seiko website. It does not seem to be as well known and we hope that our movement database is more complete and that our instructions are more helpful. As with any part of WatchSleuth we encourage people to contact us with suggestions, corrections or any other information that would make our site more useful.