Running pace calculator
Calculate running pace, speed and race time predictions.
Fill in the fields and the result will appear here automatically.
Average pace is time per kilometre; speed is distance per hour. Those arithmetic results also apply to walking. Separate race forecasts use a power law with exponent 1.06 and depend on endurance and conditions. A walking result is not thereby a validated running-race prediction.
How it works
Formula and logic
Time t = 3600h + 60m + s; one mile is exactly 1.609344 km. Pace = t/D in seconds per km and speed = 3600D/t in km/h. Race forecast T₂ = t(D₂/D)^1.06 for 5 km, 10 km, 21.0975 km and 42.195 km. Times round to the nearest second.
Example
5 km in 25 minutes gives 1500/5 = 300 s/km → 5:00/km and 12.00 km/h; mile pace is 8:03. The 10 km power-law forecast is 1500×2^1.06 ≈ 3127 s → 52:07, whereas 10 km at the same even pace takes 50:00.
Fields and units
- Distance — selected distance unit — km or mi
- Unit — km / mi
- Hours — h
- Minutes — min
- Seconds — s
How to use
- — Enter a positive distance and select kilometres or miles.
- — Enter nonnegative hours, minutes and seconds with a positive total time.
- — Compare pace per kilometre, pace per mile and average speed.
- — Even splits distribute the same average pace; race forecasts use a separate model.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- Vickers and Vertosick, 2016: recreational race predictions and marathon-transfer limitations
- Limitation
- Race forecasts are approximate and do not prescribe a safe workload or guarantee performance. Average pace describes only the distance and time entered.
FAQ
What does the Riegel-style exponent 1.06 mean?
It is an adopted power-law relationship between results at different distances, not a universal law for every runner.
Can I calculate walking pace here?
Yes, average pace and speed use only distance and time. The separate running forecasts are not validated for walking.
Why might a marathon forecast be too fast?
The model omits endurance preparation, fuelling, terrain and weather. A 2016 recreational-runner study found frequent optimistic marathon predictions.
How do I calculate pace for a target time?
Enter the planned distance and total time. That gives the even pace required, separately from power-law race predictions.
How do min/km, km/h and miles relate?
5:00/km is five minutes per kilometre and 12 km/h. Multiply kilometre pace by 1.609344 for mile pace; forecast race distances remain in kilometres.