Treadmill Calorie Calculator

The ACSM equations estimate oxygen uptake from belt speed and incline, then convert it to calories using your body weight. Incline matters far more when walking than when running.

This is an estimate of what a treadmill session cost, worked out from the published ACSM equations. It knows belt speed, incline, body weight and time, and nothing else — not your fitness, not your stride, not the day you had. The equations first turn speed and incline into an oxygen uptake, then convert that uptake into calories: uptake times body weight, divided by 1000 to reach litres, times 5 kcal per litre of oxygen, times the minutes. With the preset values — walking, 5.5 km/h, 5 % incline, 75 kg, half an hour — the belt moves about 92 metres a minute, the uptake works out at roughly 20.9 ml per kilogram per minute, and the session comes to 235 kcal. Most of the difference sits in the incline, and the incline is mostly a walker's lever: the same half hour gives 143 kcal on the flat, 235 at 5 % and 328 at 10 %. Running at 10 km/h it goes from 414 to 499 kcal at 5 %, a fifth more rather than two thirds. Two things limit the figure. Walking and running are separate equations that diverge between roughly 6 and 8 km/h, so pick the gait you were actually in. And the console will usually show something else, because it runs its own model and many consoles are never told the body weight that matters most here.