How it works
Treadmills show speed, distance per hour. Runners usually think in pace, time per kilometer or mile. Converting one to the other is a single division: 60 minutes divided by the speed.
Incline adds work, because every stride lifts your body a little. To estimate how much, this calculator uses the running equation from the American College of Sports Medicine (ACSM), which predicts the oxygen cost of running at a given speed and grade. Setting that cost equal to level running gives the level speed that takes the same effort. Each 1% of incline adds about 4.5% to the equivalent speed.
That level-ground figure is for a treadmill with no wind. Outdoors you also push against air, which is why a 1% incline is often suggested to make treadmill running feel closer to the road.
The formula
pace (min per km) = 60 ÷ speed (km/h)
pace (min per mile) = 60 ÷ speed (mph)
ACSM running equation:
VO2 = 0.2 × S + 0.9 × S × G + 3.5
(S = speed in m/min, G = incline as a fraction, VO2 in ml/kg/min)
same effort on the level: S_level = S × (1 + 4.5 × G)Worked example
A treadmill set to 10 km/h at 1% incline.
- Pace: 60 ÷ 10 = 6 minutes, so 6:00 per km. Per mile, 6 × 1.609344 = 9.66 minutes, or 9:39.
- Level equivalent: 10 × (1 + 4.5 × 0.01) = 10.45 km/h.
- That is 5:44 per km on a level belt for the same oxygen cost.
At 5% incline the same belt speed is worth 10 × (1 + 4.5 × 0.05) = 12.25 km/h on the level, about 4:54 per km.
Treadmill pace chart (km/h)
| km/h | Per km | Per mile | mph |
|---|---|---|---|
| 6.0 | 10:00 | 16:06 | 3.7 |
| 6.5 | 9:14 | 14:51 | 4.0 |
| 7.0 | 8:34 | 13:48 | 4.3 |
| 7.5 | 8:00 | 12:52 | 4.7 |
| 8.0 | 7:30 | 12:04 | 5.0 |
| 8.5 | 7:04 | 11:22 | 5.3 |
| 9.0 | 6:40 | 10:44 | 5.6 |
| 9.5 | 6:19 | 10:10 | 5.9 |
| 10.0 | 6:00 | 9:39 | 6.2 |
| 10.5 | 5:43 | 9:12 | 6.5 |
| 11.0 | 5:27 | 8:47 | 6.8 |
| 11.5 | 5:13 | 8:24 | 7.1 |
| 12.0 | 5:00 | 8:03 | 7.5 |
| 12.5 | 4:48 | 7:43 | 7.8 |
| 13.0 | 4:37 | 7:26 | 8.1 |
| 13.5 | 4:27 | 7:09 | 8.4 |
| 14.0 | 4:17 | 6:54 | 8.7 |
| 14.5 | 4:08 | 6:40 | 9.0 |
| 15.0 | 4:00 | 6:26 | 9.3 |
| 15.5 | 3:52 | 6:14 | 9.6 |
| 16.0 | 3:45 | 6:02 | 9.9 |
| 16.5 | 3:38 | 5:51 | 10.3 |
| 17.0 | 3:32 | 5:41 | 10.6 |
| 17.5 | 3:26 | 5:31 | 10.9 |
| 18.0 | 3:20 | 5:22 | 11.2 |
| 18.5 | 3:15 | 5:13 | 11.5 |
| 19.0 | 3:09 | 5:05 | 11.8 |
| 19.5 | 3:05 | 4:57 | 12.1 |
| 20.0 | 3:00 | 4:50 | 12.4 |
Treadmill pace chart (mph)
| mph | Per mile | Per km | km/h |
|---|---|---|---|
| 4.0 | 15:00 | 9:19 | 6.4 |
| 4.5 | 13:20 | 8:17 | 7.2 |
| 5.0 | 12:00 | 7:27 | 8.0 |
| 5.5 | 10:55 | 6:47 | 8.9 |
| 6.0 | 10:00 | 6:13 | 9.7 |
| 6.5 | 9:14 | 5:44 | 10.5 |
| 7.0 | 8:34 | 5:20 | 11.3 |
| 7.5 | 8:00 | 4:58 | 12.1 |
| 8.0 | 7:30 | 4:40 | 12.9 |
| 8.5 | 7:04 | 4:23 | 13.7 |
| 9.0 | 6:40 | 4:09 | 14.5 |
| 9.5 | 6:19 | 3:55 | 15.3 |
| 10.0 | 6:00 | 3:44 | 16.1 |
| 10.5 | 5:43 | 3:33 | 16.9 |
| 11.0 | 5:27 | 3:23 | 17.7 |
| 11.5 | 5:13 | 3:15 | 18.5 |
| 12.0 | 5:00 | 3:06 | 19.3 |
Questions
How do I convert treadmill speed to pace?
Divide 60 by the speed. At 12 km/h, 60 ÷ 12 = 5, so the pace is 5:00 per km. At 6 mph, 60 ÷ 6 = 10, so the pace is 10:00 per mile. For the leftover decimal, multiply by 60 to get seconds.
Should I set the treadmill to 1% incline?
If you want treadmill runs to match flat road running, 1% is a reasonable setting. Jones and Doust (1996) found that a 1% grade matched the oxygen cost of outdoor running at speeds from 10.5 to 18 km/h, roughly 6.5 to 11.2 mph. At slower speeds air resistance matters less.
Why does incline make running so much harder?
You lift your body with every stride. In the ACSM equation the climbing term is 4.5 times the incline fraction of the level cost, so 5% incline makes the same belt speed feel like running about 22% faster on the level.
Can I use this for walking?
No. The ACSM running equation is meant for running speeds, roughly above 8 km/h (5 mph). Walking has its own, different equation.
Is the speed on the treadmill display accurate?
Not always. Belt speed can drift from the displayed number, especially on older or heavily used machines, and two treadmills at the same setting can feel different. If a treadmill run feels much harder or easier than the matching outdoor pace, the display may be off.
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Sources
- Jones AM, Doust JH. A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. Journal of Sports Sciences. 1996;14(4):321-327.
- American College of Sports Medicine. ACSM’s Guidelines for Exercise Testing and Prescription. 11th ed. Wolters Kluwer; 2021. Metabolic equations for running.