4 calculators · measurements and sources
Watch tools
Check whether a watch will fit, compare cases at the same scale, choose a strap length and make sense of its accuracy. Pick the measurement you have; each tool explains the calculation and cites the watch data it uses.
Fit and size
Use the fit calculator for one watch and one wrist. Use the comparison when you are deciding between cases. Casio case length (L) stays separate from lug to lug in both.
Straps and batteries
A lug width tells you the strap width at the case; wrist size helps with length. Check the watch’s attachment and the exact battery code before ordering a part.
- Watch strap size calculatorUse your wrist and lug width to read published two-piece and NATO strap length grids.
- Parts compatibilityCheck a named aftermarket part against an exact watch model, with the source’s fit statement.
- Watch battery swap checkerCheck the two printed codes and their chemistry before treating one cell as a replacement.
- Watch battery finderStart with the code printed on the old cell or the movement in your watch.
Accuracy and movements
Compare your own reading with a published calibre range. A single timegrapher reading is a snapshot, so the tool shows its assumptions and the cited specification.
Identify a watch
Start with the model and calibre printed on the case back; a serial can narrow a production year without proving an exact date.
How to read a result
Published case sizes, movement specifications and strap grids are cited where they appear. If sources disagree, the tool shows the reported values instead of silently averaging them. You can follow the numbered references below each calculator to the original document or product page.
Wrist fit is an estimate from the flat width of your wrist; enter that width if you measured it. A drawing shows dimensions, not the appearance or feel of a particular watch. Your timegrapher and accuracy readings come from you and are not a diagnosis of the movement.
