Converting running pace to speed in km/h and mph
Speed in km/h is 60 divided by your pace in minutes per kilometre. A 5:00/km pace is 60 ÷ 5 = 12 km/h. For mph, divide that by 1.609344 to get 7.46. Pace and speed describe the same run from opposite ends, and the treadmill is where the difference stops being academic.
Pace and speed are reciprocals
Pace answers how long a unit of distance takes. Speed answers how much distance fits in an hour. One is the other turned upside down, which is why the arithmetic is a division rather than a scaling factor.
This also explains a thing that surprises people: equal steps in pace are not equal steps in speed. Going from 6:00 to 5:00 per kilometre adds 2 km/h. Going from 4:00 to 3:00 adds 5 km/h for the same one minute improvement.
Why treadmills force the conversion on you
Gym treadmills are dialled in speed, almost always km/h outside the United States and mph inside it. Training plans are written in pace. So a runner with a session calling for 8 kilometres at 4:30/km stands in front of a machine that wants to be told 13.3.
Getting it wrong is expensive in a way that a road run is not. On the road you drift back to the right effort. On a belt moving at a fixed speed you hold the wrong number for the full session.
Pace, km/h and mph chart
Kilometre paces from 3:00 to 8:00 with their speed equivalents.
| Pace per km | Pace per mile | Speed | Speed |
|---|---|---|---|
| 3:00 /km | 4:50 /mi | 20.0 km/h | 12.4 mph |
| 3:15 /km | 5:14 /mi | 18.5 km/h | 11.5 mph |
| 3:30 /km | 5:38 /mi | 17.1 km/h | 10.7 mph |
| 3:45 /km | 6:02 /mi | 16.0 km/h | 9.9 mph |
| 4:00 /km | 6:26 /mi | 15.0 km/h | 9.3 mph |
| 4:15 /km | 6:50 /mi | 14.1 km/h | 8.8 mph |
| 4:30 /km | 7:15 /mi | 13.3 km/h | 8.3 mph |
| 4:45 /km | 7:39 /mi | 12.6 km/h | 7.8 mph |
| 5:00 /km | 8:03 /mi | 12.0 km/h | 7.5 mph |
| 5:15 /km | 8:27 /mi | 11.4 km/h | 7.1 mph |
| 5:30 /km | 8:51 /mi | 10.9 km/h | 6.8 mph |
| 5:45 /km | 9:15 /mi | 10.4 km/h | 6.5 mph |
| 6:00 /km | 9:39 /mi | 10.0 km/h | 6.2 mph |
| 6:15 /km | 10:04 /mi | 9.6 km/h | 6.0 mph |
| 6:30 /km | 10:28 /mi | 9.2 km/h | 5.7 mph |
| 6:45 /km | 10:52 /mi | 8.9 km/h | 5.5 mph |
| 7:00 /km | 11:16 /mi | 8.6 km/h | 5.3 mph |
| 7:15 /km | 11:40 /mi | 8.3 km/h | 5.1 mph |
| 7:30 /km | 12:04 /mi | 8.0 km/h | 5.0 mph |
| 7:45 /km | 12:28 /mi | 7.7 km/h | 4.8 mph |
| 8:00 /km | 12:52 /mi | 7.5 km/h | 4.7 mph |
Both speeds, always on screen
Milemark shows km/h and mph as two tiles under the converted pace, so a 5:15/km entry reads 11.4 and 7.1 without a second lookup. Whichever unit the machine in front of you uses, the number is already there.
Questions about this
What speed is a 6:00 min/km pace?
10 km/h, or 6.21 mph. It is the cleanest conversion in running, which is why 10 km/h is such a common treadmill setting.
Should I set the treadmill by pace or speed?
You have no choice, the belt takes speed. Convert your pace target once before you step on rather than adjusting mid-interval.