How it works
Pace is the time it takes to cover one kilometre or one mile. Runners use it instead of speed because it maps directly to a watch: “5:00 per km” tells you exactly how fast to go. The calculator turns any distance and time into pace and speed.
pace per km = time ÷ distance in km · pace per mile = pace per km × 1.609344 speed (km/h) = distance in km ÷ time in hours · 1 mile = 1.609344 kmWorked examples. 10 km in 50:00 → 5:00 per km, 8:03 per mile, 12 km/h (7.46 mph). Kept up for a full marathon (42.195 km) that is 3:30:59. A 5 km parkrun in 30:00 is 6:00 per km and 10 km/h.
Common race distances
| Race | km | miles | At 6:00/km |
|---|---|---|---|
| 5K | 5 | 3.11 | 30:00 |
| 10K | 10 | 6.21 | 1:00:00 |
| Half marathon | 21.0975 | 13.1 | 2:06:35 |
| Marathon | 42.195 | 26.2 | 4:13:10 |
Training paces
- Easy runs: about 60–90 seconds per km slower than your 10K pace — you should be able to talk.
- Tempo runs: roughly your 10K to half-marathon pace for 20–40 minutes.
- Race predictions: the marathon line assumes you hold the same pace. Most runners slow down over longer races, so treat it as a best case; a marathon is usually 15–30 seconds per km slower than 10K pace.
Weather, hills and heat all slow your pace; compare similar runs. To convert distances, use km to miles. To see how many calories you need on training days, try the TDEE calculator, and for split times add up with the time calculator.