Treadmill pace converter
Free, from Runsei. No account, nothing stored on our side.
What a speed and incline on the belt is worth on a flat road, or the belt setting that matches the road pace you had in mind. Kilometres or miles, pace or speed.
5:30 /km · 8:51 /mile · 10.9 km/h · 6.8 mph
5:30 /km at 1% costs about what 5:30 /km costs outdoors on the flat. At 1% the two are the same pace; that is the rule of thumb this page is built on.
What this cannot know
- It is an average. The studies measured groups of runners; your own cost of running on a belt can sit a few percent either side.
- It matches energy cost, not feel. Belts differ in cushioning, and heat builds faster indoors, so the same effort can feel harder or easier.
- Uphill only. Few belts decline, and downhill running adds muscle damage that an energy figure does not capture. Incline is limited to 0–15%.
- Check your belt. Many treadmills are not calibrated to their display.
Treadmill pace chart
The belt pace, per kilometre, that costs the same effort as a flat road pace, at each incline. The first column is the pace on the road; the others are what to set on the belt. Use the converter above for anything between the rows.
| Road pace /km | 0% incline | 1% incline | 2% incline | 3% incline | 4% incline | 5% incline |
|---|---|---|---|---|---|---|
| 4:00 | 3:47 | 4:00 | 4:13 | 4:27 | 4:42 | 4:57 |
| 4:30 | 4:16 | 4:30 | 4:45 | 5:01 | 5:17 | 5:34 |
| 5:00 | 4:44 | 5:00 | 5:17 | 5:34 | 5:52 | 6:11 |
| 5:30 | 5:13 | 5:30 | 5:48 | 6:07 | 6:27 | 6:48 |
| 6:00 | 5:41 | 6:00 | 6:20 | 6:41 | 7:03 | 7:25 |
| 6:30 | 6:09 | 6:30 | 6:52 | 7:14 | 7:38 | 8:02 |
| 7:00 | 6:38 | 7:00 | 7:23 | 7:48 | 8:13 | 8:39 |
Why 1%?
Outdoors you push through air; on a belt you do not. In a study that measured the oxygen cost of running at several speeds on a treadmill and outdoors, a belt gradient of 1% was the one that best reproduced the outdoor cost. That is the origin of the usual advice to set the treadmill to 1%, and it is why the 1% column above equals the road pace exactly.
What the other inclines are worth
Each extra percent of gradient raises the energy cost of a step. The converter uses a published curve of running cost against slope, fitted to measurements from steep downhill to steep uphill, and asks what speed on a flat road costs the same. That is how a 5:30 per kilometre run at 5% turns out to be worth about 4:27 on the flat road. A flat belt is the same arithmetic in the other direction: a little easier than the road, so its road equivalent is slower than the number on the display.
Sources
- A belt at 1% matches flat outdoor running at the same speed. Measured oxygen cost of running at several speeds on a treadmill at different gradients against the same runners outdoors: 1% was the gradient that best reproduced the outdoor cost, the difference being air resistance. Jones & Doust (1996), Journal of Sports Sciences 14(4), 321-327.
- What each extra percent of incline costs. Metabolic cost of running measured on a treadmill across slopes from -45% to +45%, fitted as a polynomial. The same fit is used for grade-adjusted pace in Runsei itself. Minetti et al. (2002), Journal of Applied Physiology 93(3), 1039-1046.