Pace Calculator
Enter any two of distance, time, and pace, and the third is solved instantly — with pace shown per kilometre and per mile, plus speed in km/h. Leave the field you want solved empty.
Solve pace, time, or distance
Example: 10 km in 50:00 → 5:00 /km.
Pace, speed, and the two-of-three rule
Distance, time, and pace are locked together: pace = time ÷ distance. Given any two, the third follows — 10 km in 50 minutes is 5:00 per km, which is also 8:03 per mile and 12 km/h. Runners think in pace rather than speed because splits on a watch and markers on a course arrive per kilometre or mile.
Using it for race planning
Work backwards from a goal: enter the race distance and target time to get the pace you must average, then test that pace over shorter training runs. For negative-split strategies, plan the first half slightly slower than average and the second slightly faster — the average still has to match the number this calculator gives you.
Frequently asked questions
How do I enter time and pace?
Times accept h:mm:ss, mm:ss, or plain minutes (50 means 50 minutes). Pace is mm:ss per your chosen distance unit — 5:00 with kilometres selected means five minutes per km.
How do km and mile paces relate?
A mile is 1.609 km, so the per-mile figure is always about 61% larger: a 5:00/km runner is at 8:03/mi. The calculator shows both so race charts in either unit are usable.
What pace do I need for common goals?
A 25-minute 5K needs 5:00/km; a 2-hour half marathon needs 5:41/km; a 4-hour marathon needs 5:41/km as well — the half at that pace simply takes half as long. Enter your own target distance and time to see the required pace exactly.
Does the calculator account for hills or fatigue?
No — it is pure arithmetic on average pace. For pacing strategy, runners typically plan slightly slower early kilometres and use average pace as the anchor, not a fixed split for every km.
Values are processed locally in your browser and never transmitted. Train sensibly and consult a professional before major changes to exercise intensity. See the methodology page.