How to use it
- Choose Activity: Walking or Running.
- Choose the Speed unit and type the Belt speed shown on the treadmill.
- Type the Incline in percent, or 0 for a level belt.
- Read Pace per kilometre and Flat-road pace per kilometre, and compare the Oxygen cost at other inclines, same speed table.
The ACSM equations for walking and running
The American College of Sports Medicine equations estimate the oxygen cost of steady walking and running from the speed and the grade. The result is in millilitres of oxygen per kilogram of body weight per minute. The 3.5 is the resting cost, so the equation gives the total cost of the activity.
Walking is stated for 1.9 to 3.7 mph (3.05 to 5.95 km/h). Running is stated for speeds above 5.0 mph, and from 3.0 mph for jogging. Outside these ranges the page shows a note.
walking: VO2 = 0.1 × S + 1.8 × S × G + 3.5
running: VO2 = 0.2 × S + 0.9 × S × G + 3.5
S speed in metres per minute (1 mph = 26.8 m/min)
G grade as a fraction (5 % is 0.05)
MET = VO2 ÷ 3.5Flat-road pace and the 1 % rule
Jones and Doust (1996) ran nine trained male runners on a treadmill at grades from 0 to 3 % and on a flat outdoor road, at speeds from 2.92 to 5.0 m/s. The oxygen cost on the road matched a 1 % grade at every speed. A level belt is therefore a little easier than outdoor running at the same speed.
The flat-road speed of the same effort is found by setting the running cost of the treadmill run equal to the outdoor cost, which is 0.209 per metre per minute of speed at 1 % (0.2 + 0.9 × 0.01). This is a derivation from the 1 % result, so it is an estimate.
flat-road speed = speed × (0.2 + 0.9 × G) ÷ 0.209
At 10 km/h and 5 %: 10 × (0.2 + 0.045) ÷ 0.209 = 11.72 km/hWhat this calculator does not include
- Wind, air resistance and the surface of an outdoor run beyond the 1 % result.
- Downhill running and walking, which the equations do not cover on this page.
- Calories. The page gives oxygen cost and METs; a calorie figure would also need your body weight and the time.
Worked example: running at 10 km/h and 5 %
The speed is 166.7 m/min. The running cost is 0.2 × 166.7 + 0.9 × 166.7 × 0.05 + 3.5 = 44.3 ml/kg/min, which is 44.3 ÷ 3.5 = 12.7 METs.
The pace is 3600 ÷ 10 = 360 seconds per kilometre, which is 6:00 per kilometre or 9:39 per mile. The flat-road speed of the same effort is 11.72 km/h, a pace of 5:07 per kilometre.
| Incline | ml/kg/min | METs |
|---|---|---|
| 0% | 36.8 | 10.5 |
| 1% | 38.3 | 11.0 |
| 2% | 39.8 | 11.4 |
| 3% | 41.3 | 11.8 |
| 5% | 44.3 | 12.7 |
| 10% | 51.8 | 14.8 |
| 15% | 59.3 | 17.0 |
Frequently asked questions
What is the 1 % rule?
Jones and Doust (1996) found that running on a treadmill at a 1 % grade costs the same oxygen as running outdoors on the flat at the same speed. The calculator uses this result to convert an uphill treadmill run into a flat-road pace.
Is a level treadmill the same as outdoor running?
Not quite. A level belt at 10 km/h costs about the same as outdoor running at 9.57 km/h, so the outdoor pace is a little slower than the belt pace for the same effort.
What is a MET?
A MET is the oxygen cost of resting, set by convention at 3.5 ml of oxygen per kilogram per minute. Dividing an activity's oxygen cost by 3.5 gives how many times the resting cost it is.
Why does the walking equation stop at about 3.7 mph?
The equation is stated for walking from 1.9 to 3.7 mph (3.05 to 5.95 km/h). Faster than that, the page shows a note, because the equation is outside the range it was stated for.
Are the figures exact for my treadmill?
No. Belts are not always calibrated, and the equations estimate a steady effort for an average person. Use the pace as a guide and check it against your own timing.
Sources
- J. Ross, ACSM Metabolic Calculations (Wake Forest University): the walking and running equations, the speed ranges and 1 MET = 3.5 ml/kg/min
- Jones and Doust (1996): A 1% treadmill grade most accurately reflects the energetic cost of outdoor running, J Sports Sci 14(4):321-327
- Wikipedia: Metabolic equivalent of task (MET defined as 3.5 ml of oxygen per kg per minute by convention)
Figures and text last checked on Tuesday, November 10, 2026.