العربية

Pace calculator

Calculate time, distance or pace from the other two with explicit units.

Calculations stay in this browser, without requests carrying your entries or automatic storage. The bounded synchronous calculation has no background progress or cancellation task.

Choose the missing value and enter the other two. Time and pace must be positive HH:MM:SS with an optional .mmm fraction of 1–3 digits. Hours can exceed 24, up to 999999; minutes and seconds are 00–59. Distances are positive, below 1000000000000, with at most 12 whole and 6 fractional digits. A mile is exactly 1.609344 km; distance and pace units are independent.

Time = distance × pace after exact unit conversion. Input times are exact milliseconds; results use fractions before rounding. Durations round to the nearest millisecond, halfway upward; distances and speeds round to 6 decimals. A small positive result may display zero after rounding: consult the exact fraction. Derived durations must not exceed 999999:59:59.999 and distances must remain below 1000000000000. This is arithmetic, not training or health advice.

How to use

Choose the value to calculate. Enter the other two, using HH:MM:SS with an optional .mmm fraction for durations. Independently select km or international miles for distance and pace, then calculate.

Try an example

5 km in 00:30:00 gives a pace of 00:06:00.000 per km and a speed of 10 km/h. At 00:30:00 per km, 100 km takes 50:00:00.000, without wrapping at 24 hours.

Support & limits

The international mile equals exactly 1.609344 km. Time equals distance multiplied by pace after unit conversion. Integer milliseconds and fractions are used until output; durations then round to the nearest millisecond, halfway upward, and distances and speeds to 6 decimals. Exact fractions distinguish actual zero from rounding to zero. Minutes and seconds are 00–59, hours allow up to 6 digits, and scalar fields reject line breaks. No dates, time zones, assumed return trips, health advice or training guidance are involved.

Common questions

Can I use distance in miles and pace per kilometer?

Yes. The two units are reconciled internally with exact fractions. Changing an input unit changes the interpretation of the entered number; it does not automatically convert that number.

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