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

Period Seconds (s)

Required number input.

Gravity Meters Per Second Squared (m/s2)

Required number input.

Effective small-angle pendulum length for a target complete oscillation period. 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]

Length Meters (m)

The resulting length meters 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.

• Pendulum Period

  Small-angle ideal pendulum period in seconds from effective length and local gravitational acceleration.

• Seconds Pendulum Length

  Small-angle pendulum length for a two-second full period (one-second half swing) at local gravity.

• Bracelet Link Adjustment

  Minimum whole removable bracelet links to reduce length by at least a target amount.