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

Measured Hertz (Hz)

Required number input.

Nominal Hertz (Hz)

Required number input.

Signed quartz oscillator frequency error in parts per million relative to nominal frequency. 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]

Error Ppm (ppm)

The resulting error ppm 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.

• Seconds Gained Per Day

  Signed seconds gained per day from a frequency error in parts per million.

• Moonphase Drift Per Year

  Signed lunar-phase error in equivalent lunar days per Julian year from the displayed and true synodic cycle lengths.

• Daily Rate To Annual Drift

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