Pace Calculator: Running Pace, Time, Distance and Splits
Work out running pace, finishing time or distance from the other two, in km, miles or metres or for a 5K, 10K, half marathon or marathon. Pace per km and mile, km/h and mph, and a split table. Nothing is sent.
Enter two of distance, time and pace to work out the third.
About the Pace Calculator
The Pace Calculator works out any one of time, distance and pace from the other two. Enter a distance and a finishing time to find your pace; enter a distance and a pace to predict your finishing time; or enter a time and a pace to see how far you would get. The result shows the pace per kilometre and per mile, the speed in kilometres and miles per hour, and a split table that lists the elapsed time at every kilometre or mile of the run.
Distances can be typed in kilometres, miles or metres, or picked from the common road races: 5K, 10K, the half marathon of 21.0975 km and the marathon of 42.195 km. Times are typed as hours, minutes and seconds, such as 1:45:30, as minutes and seconds, such as 25:30, or as a plain number of minutes.
This is an estimate, not medical advice. The calculator assumes an even pace on a flat course; hills, heat, wind and fatigue change what is realistic on the day.
How to use the pace calculator
Steps
- Choose what to calculate: Pace, Time or Distance.
- Pick a race distance or choose Custom and type a distance with its unit.
- Type the time as h:mm:ss or the pace as mm:ss per km or per mile, depending on what you are solving for.
- Read the result and switch the split table between kilometres and miles.
Even splits
The split table assumes you run every kilometre or mile at the same pace. Many runners aim for even or slightly negative splits, running the second half a little faster than the first, so treat the table as a target to adjust rather than a fixed plan.
The formulas
One international mile is exactly 1,609.344 metres, so a pace per mile is the pace per kilometre multiplied by 1.609344.
Worked examples
- Marathon in 3:30:00: 12,600 seconds over 42.195 km is a pace of 4:59 per km or 8:01 per mile, a speed of 12.06 km/h or 7.49 mph.
- 10K at 5:00 per km: the finishing time is 50:00.
- One hour at 8:00 per mile: you would cover 7.5 miles, or 12.07 km.
- Half marathon in 1:45:30: the table lists 21 whole kilometres and a final row at 21.0975 km, 1:45:30.
Privacy
Nothing is uploaded; the calculation runs in your browser and never leaves your device.
Related tools
Convert between km/h, mph and metres per second with the Speed Converter, switch between kilometres and miles with the Length Converter, or set training intensity with the Target Heart Rate Calculator.
Sources
- World Athletics. Competition Rules, Book C2.1, Technical Rules, rule 55 (road races): the standard road race distances, including the marathon of 42.195 km and the half marathon of 21.0975 km.
- National Institute of Standards and Technology. NIST Handbook 44, Appendix C: General Tables of Units of Measurement: the international mile of exactly 1,609.344 m.
Open-source credits
The calculations are implemented in-house in TypeScript. They follow the standard relations between distance, time and pace, the World Athletics road race distances and the international mile, and no third-party code is used.
Frequently asked questions
How do I calculate my running pace?
Divide the time by the distance. A 10 km run in 50 minutes is 50 ÷ 10 = 5 minutes per kilometre. Multiply by 1.609344 for the pace per mile, here about 8:03.
How long is a half marathon and a marathon?
A marathon is 42.195 km, about 26.2 miles, and a half marathon is exactly half of it, 21.0975 km or about 13.1 miles. The 5K and 10K are 5 and 10 km, about 3.11 and 6.21 miles.
What pace do I need for a sub-4-hour marathon?
About 5:41 per kilometre or 9:09 per mile, or faster: 4 hours over 42.195 km is 341.3 seconds per kilometre. Choose Time, pick the Marathon preset and type a pace to see the finishing time it gives, or choose Pace and type 4:00:00 to see the exact target.
How do I type the time and pace?
Type hours, minutes and seconds separated by colons, such as 1:45:30, minutes and seconds such as 25:30, or a plain number of minutes such as 45. Seconds may have decimals, such as 4:59.5.
Does the split table allow for hills or a negative split?
No. It assumes an even pace for every kilometre or mile. Use it as a starting point and adjust for the course and how you plan to run it.