How to calculate running pace
Your pace is how long it takes to cover one unit of distance. It's calculated as total time ÷ distance. For example, running 5 km in 25 minutes is a pace of 5:00 per km.
Predicting race times
The Riegel formula predicts your time at a new distance from a known one: T₂ = T₁ × (D₂ ÷ D₁)^1.06. The 1.06 exponent reflects that you slow down slightly as distance increases. It's remarkably accurate for well-trained runners across 5K to marathon.
Running pace chart
Pace per kilometre and per mile, the matching speed, and the finish time for each race distance if you hold that pace the whole way. For a realistic prediction from a recent race result, use the calculator — it allows for fatigue over longer distances.
| Per km | Per mile | km/h | mph | 5K | 10K | Half | Marathon |
|---|---|---|---|---|---|---|---|
| 3:00 | 4:50 | 20 | 12.4 | 15:00 | 30:00 | 1:03:18 | 2:06:35 |
| 3:15 | 5:14 | 18.5 | 11.5 | 16:15 | 32:30 | 1:08:34 | 2:17:08 |
| 3:30 | 5:38 | 17.1 | 10.7 | 17:30 | 35:00 | 1:13:50 | 2:27:41 |
| 3:45 | 6:02 | 16 | 9.9 | 18:45 | 37:30 | 1:19:07 | 2:38:14 |
| 4:00 | 6:26 | 15 | 9.3 | 20:00 | 40:00 | 1:24:23 | 2:48:47 |
| 4:15 | 6:50 | 14.1 | 8.8 | 21:15 | 42:30 | 1:29:40 | 2:59:20 |
| 4:30 | 7:15 | 13.3 | 8.3 | 22:30 | 45:00 | 1:34:56 | 3:09:53 |
| 4:45 | 7:39 | 12.6 | 7.8 | 23:45 | 47:30 | 1:40:13 | 3:20:26 |
| 5:00 | 8:03 | 12 | 7.5 | 25:00 | 50:00 | 1:45:29 | 3:30:59 |
| 5:15 | 8:27 | 11.4 | 7.1 | 26:15 | 52:30 | 1:50:46 | 3:41:31 |
| 5:30 | 8:51 | 10.9 | 6.8 | 27:30 | 55:00 | 1:56:02 | 3:52:04 |
| 5:45 | 9:15 | 10.4 | 6.5 | 28:45 | 57:30 | 2:01:19 | 4:02:37 |
| 6:00 | 9:39 | 10 | 6.2 | 30:00 | 1:00:00 | 2:06:35 | 4:13:10 |
| 6:15 | 10:04 | 9.6 | 6 | 31:15 | 1:02:30 | 2:11:52 | 4:23:43 |
| 6:30 | 10:28 | 9.2 | 5.7 | 32:30 | 1:05:00 | 2:17:08 | 4:34:16 |
| 6:45 | 10:52 | 8.9 | 5.5 | 33:45 | 1:07:30 | 2:22:24 | 4:44:49 |
| 7:00 | 11:16 | 8.6 | 5.3 | 35:00 | 1:10:00 | 2:27:41 | 4:55:22 |
| 7:15 | 11:40 | 8.3 | 5.1 | 36:15 | 1:12:30 | 2:32:57 | 5:05:55 |
| 7:30 | 12:04 | 8 | 5 | 37:30 | 1:15:00 | 2:38:14 | 5:16:28 |
| 7:45 | 12:28 | 7.7 | 4.8 | 38:45 | 1:17:30 | 2:43:30 | 5:27:01 |
| 8:00 | 12:52 | 7.5 | 4.7 | 40:00 | 1:20:00 | 2:48:47 | 5:37:34 |
What is a 5 minute per km pace in minutes per mile?
8:03 per mile. Multiply the per-km pace by 1.609 to get the per-mile pace. It's 12 km/h, or 7.5 mph.
What pace do I need for a sub-2-hour half marathon?
Faster than 5:41 per km (9:09 per mile), held for all 21.1 km.
What pace is a 4-hour marathon?
5:41 per km, or 9:09 per mile — the same pace as a 2-hour half marathon, since a marathon is exactly twice as far.
Why is my predicted marathon slower than 8× my 5K?
Because endurance fades over distance. The formula accounts for that natural slowdown, so longer races are predicted at a slightly slower pace.
Pace vs speed — what's the difference?
Pace is time per distance (min/km); speed is distance per time (km/h). They're two views of the same thing.