Place phone mic firmly against the watch caseback or crown in a quiet room.

Tap the Watch bar to pick your watch model or keep Auto-Detect active to identify the beat rate dynamically.

• Rate (s/d): Accuracy in seconds gained (+) or lost (−) per day. Ideal: ±0 to ±5 s/d.
• Beat Error (ms): Escapement symmetry between tick & tock. Ideal: < 0.5 ms.
• Amplitude (°): Balance wheel rotation angle. Healthy: 260° – 310°.

Test across positions (Dial Up, Crown Down, etc.) and tap Save to track maximum Delta variance.