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WatchtheDetails

Casio serial number lookup

A Casio serial doesn’t tell the year. The case back’s module number does tell you the electronics and the manual: 5611 is 91 models in Casio’s index.

The module is the 3–4 digit number in a small box (e.g. 5611); the model reads like GA-2100 or F-91W.

Try

Not a date

Module 5611: 91 models, no date

  1. Step 1: 5611module 5611 → the electronics inside (91 models in Casio's index); not a date[2][4]

Read about module 5611: battery, functions and the manual.[4]

Models on this module (91):

GA-2100, GA-2100, GA-2100AB25, GA-2100AH, GA-2100BCE, GA-2100BM, GA-2100BP, GA-2100BWP, GA-2100CA, GA-2100CC, GA-2100CM, GA-2100FF and 79 more

Casio case back: Module 5611: 91 models, no dateWATER RESIST · STAINLESS STEEL BACK · WATER RESIST · STAINLESS STEEL BACK · WATER RESIST · STAINLESS STEEL BACK · 56111module number, in its box··-····model number
Our drawing, not a photo: the module number in its box, the model number under it.

Sources checked · How we source numbers

How it works

No date in the serial

Casio does not use unique serials on all its watches, and where there is one it does not encode a date the way Seiko’s does[1][2]. One site says some higher-end serials have six characters with O, N or D second, and that solar models carry an 8-character batch code[3]; it gives no way to read either, and the other sources disagree, so the decoder shows such codes as they are.

Module and model

The module number, 3–4 digits often in a box, names the electronics; the model number names the watch[2][3]. Casio’s manual search links 3,274 models to 590 modules[4]; enter either and the decoder finds the other, and links our module page where we have one.

Dating a Casio anyway

The closest you get is the module’s introduction year: the watch can’t be older than its module. It is coarse, and the list of introduction years is not in anything we could read[2].

What we couldn’t verify

  • A Casio serial with a known production date: no source gives one.
  • Module introduction years: one site says it has them, but they are behind a form.
  • A serial or date policy from Casio itself.

Casio modules with a page

63 modules have a page of ours with the battery, functions and manual; the most used first. Below, the examples from our sources.

  • 5611

    from the source

    The source says

    no date. Module 5611 identifies the electronics; the manual for the GA-2100 setting instructions is found by searching the module number[2]

    Our decoder says

    Module 5611: 91 models, no date open it

  • 3229

    from the source

    The source says

    identifies the internal movement (3-4 digit module code); no date[2]

    Our decoder says

    Module 3229: 118 models, no date open it

  • 593

    from the source

    The source says

    identifies the internal movement (3-digit module); no date[2]

    Our decoder says

    Module 593: 13 models, no date open it

Questions

Does a Casio serial number tell the year?

No. Casio does not put a date code in its serials, and many Casio watches have no serial at all. One collector site reads some G-Shock serials like a Seiko date code; other sources disagree, and none checks it against a watch of known date, so we don’t decode it.

What is the module number on a Casio?

The 3–4 digit number in a small box on the case back: it names the electronics inside, and Casio files its manuals by it. Module 5611 is used by 91 models in Casio's own index; many models share one module.

How do I find the manual for my Casio?

Search Casio’s manual site by the module number. For module 5611 that is the 5611 user’s guide (PDF).

Which module is in the Casio F-91W?

F-91W uses module 593, according to Casio's own manual index.

Sources

Documents checked · Report a wrong number

  1. 1Majestix Collection — How to Check Casio Watch Serial Number Correctly · html · read
  2. 2Watch Identifier — Casio Watch Identifier: Module and Model Numbers Explained · html · read
  3. 3Serial-Number-Decoder.co.uk — Casio serial number decoder. Date a Casio by serial number, batch code or module · html · read
  4. 4Casio Computer Co., Ltd. — Watch manual search JSON (US locale), manual_search.support.json · json · read