Running Pace Calculator
Free to use, with no sign up. Your entries stay in this browser; calculations run on your device.
Pace, time and distance
Pace = time / distance. Time = pace × distance. Distance = time / pace. One mile = 1.609344 km.
Race time predictor
Use a recent race result to estimate a time for another distance. Both distances use the same selected unit.
Predicted finish time
Riegel: T₂ = T₁ × (D₂/D₁)^1.06. T₁ is your known race time; D₁ and D₂ are the known and target distances in the same units. Tested in Vickers & Vertosick (2016).
Marathon predictions run optimistic for recreational runners. Vickers & Vertosick (2016) tested an exponent of 1.07 and found poorer calibration for marathons than shorter races. This calculator uses the conventional 1.06 and assumes you have trained for the target distance.
For general information only; not medical advice.
How to use this tool
Choose km or miles. Enter any two of distance, time and pace, leaving the third blank, then select Calculate. Use M:SS or H:MM:SS for time.
Frequently asked questions
How do I enter time and pace?
Use M:SS, such as 25:00 for 25 minutes, or H:MM:SS, such as 1:50:20. A plain number means minutes. Pace is the time for one kilometre or one mile, depending on your chosen unit.
Can I calculate distance or total time?
Yes. Leave distance blank to calculate it from time and pace. Leave time blank to calculate it from distance and pace. Leave pace blank to calculate it from distance and time.
How long are the race presets?
5K is 5 km, 10K is 10 km, a half marathon is 21.0975 km and a marathon is 42.195 km. Presets convert to miles when you choose miles.
How reliable is the race predictor?
Riegel estimates a time from another race result, assuming you are prepared for the target distance. Course, weather and training matter. Marathon predictions can be optimistic for recreational runners; the prediction is not a promise.