Use this horology calculation to interpret a stated watch, clock, timing-machine, water-resistance, alarm, or historical respiratory-timing quantity under its defined convention.

Index Movement

Required number input.

Sensitivity Seconds Per Day Per Unit (s/day/unit)

Required number input.

Predicted signed daily-rate change from index movement and measured sensitivity in seconds per day per index unit. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Change Seconds Per Day (s/day)

The resulting change seconds per day returned as a number.

• Mechanical-watch amplitude and beat measurements depend on lift angle, position, state of wind, movement condition, instrument setup, and elapsed sampling. ATM markings are test-pressure classifications rather than literal safe diving depths.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Confirm movement specifications and measure in multiple positions and power states; follow the manufacturer's water-resistance guidance and obtain pressure testing after case service.

• Daily Rate To Annual Drift

  Signed clock drift over a supplied year length in days from seconds gained or lost per day.

• Daily Rate To Monthly Drift

  Signed clock drift over a specified number of calendar days from seconds gained or lost per day.

• Daily Rate To Weekly Drift

  Signed accumulated clock drift over a seven-day week from seconds gained or lost per day.