Quick Reference Guide for Watch Mechanical Health & Accuracy
Measures how many seconds per day the watch gains or loses. It indicates whether the movement is running fast (+) or slow (-) compared to real time.
| Category | Value |
|---|---|
| Ideal Target | 0 s/d |
| COSC Chronometer Standard | -4 to +6 s/d |
| Everyday / Vintage Calibers | ±10 to ±15 s/d |
The rotation angle (in degrees) of the balance wheel's swing. Reflects how efficiently power transfers from the mainspring through the gear train to the escapement.
| Category | Value |
|---|---|
| Healthy Modern Swiss Calibers | 270° – 310° |
| Japanese (e.g. Seiko) / Lower Amp | 220° – 270° |
| Service Required (at full wind) | < 250° |
The time difference between the "tick" and the "tock" (the split-second balance symmetry between the clockwise and counter-clockwise swing).
| Category | Value |
|---|---|
| Excellent Alignment | 0.0 – 0.5 ms |
| Generally Acceptable | < 0.8 ms |
| Out of Alignment / Unreliable | > 1.0 ms |
