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Free Running Pace Calculator

Calculate pace, time, or distance for running, cycling, and walking. Metric and imperial, with finish-time predictions for 5K, 10K, half, and marathon.

Works offline once loaded

Goal presets

5:00
per km Β· 12.00 km/h
Cumulative splits
1 km5:00
2 km10:00
3 km15:00
4 km20:00
5 km25:00
6 km30:00
7 km35:00
8 km40:00
9 km45:00
10 km50:00
Finish times at this pace
5K23:59
10K50:00
Half Marathon1:50:19
Marathon3:50:01

Predicted with Riegel's formula from your entered run β€” longer races assume a slightly slower sustainable pace.

Enter time as MM:SS (e.g. 50:00) or HH:MM:SS for longer efforts. Works for running, walking, cycling, swimming, or rowing β€” just match the distance unit.

Common uses

  • Marathon & Half-Marathon PacingFind the pace you need to hit your goal marathon or half-marathon finish time.
  • 5K and 10K Race PacingCalculate target pace and splits for your next 5K or 10K.
  • Cycling Speed & TimeWork out average speed, ride time, or distance for cycling sessions.
  • Walking Pace & Step GoalsCalculate walking pace and how long a distance will take at your speed.
  • Treadmill Pace ConversionConvert between pace and the speed setting (km/h or mph) shown on a treadmill.

How It Works

All calculations run directly in the browser using plain arithmetic β€” no server, no library. Given any two of distance, time, and pace, the tool solves for the third using division and multiplication on seconds, then renders cumulative splits and race-time predictions instantly as you type.

  1. 1
    Choose what to solve for
    Pick whether you want to find your pace, your finish time, or how far you can go. The two fields you fill in become the inputs; the third is what the calculator derives.
  2. 2
    Time strings are parsed into seconds
    The hand-written parseTime function accepts HH:MM:SS, MM:SS, or bare seconds, converting everything to a single number of seconds so the arithmetic stays simple and unit-consistent.
  3. 3
    One division produces the answer
    Pace is time divided by distance (seconds per km or mile); finish time is pace multiplied by distance; distance is total time divided by pace per unit. Speed in km/h or mph is derived as 3600 divided by seconds-per-unit.
  4. 4
    Splits and race predictions are computed from the same pace
    Cumulative splits multiply pace by each whole-unit marker up to your distance. Race predictions for 5K, 10K, half, and full marathon use the Riegel formula (T2 = T1 Γ— (D2/D1)^1.06) when you supplied an actual race performance, or simple pace Γ— distance otherwise.

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Frequently Asked Questions