Treadmill calories

How it’s calculated

With the ACSM (American College of Sports Medicine) metabolic equations, the same ones the Evzia app uses. They work out the extra oxygen you use when you move, in milliliters per kilo of body weight and minute, with the speed in meters per minute and the incline as a fraction (a 5% incline is 0.05):

Walking (below 8 km/h): oxygen = 0.1 × speed + 1.8 × speed × incline
Running (from 8 km/h): oxygen = 0.2 × speed + 0.9 × speed × incline
Net calories = oxygen × weight (kg) ÷ 1000 × 5 × minutes

The first part of each equation is the cost of moving forward, and the second, the cost of climbing. Each liter of oxygen is about 5 kcal. The ACSM equations also add 3.5, the oxygen you use at rest; it isn’t added here, because that burn is already in your maintenance: these are net calories.

Walking or running

Running burns more per kilometer than walking: when you walk, your body makes use of the swing of each step, and when you run you have to push off with every stride. On flat ground, the running equation gives twice as much per kilometer. The walking one is meant for about 3 to 6 km/h, and the running one for more than 8 km/h (or from about 5 km/h if you’re really jogging). Between 6 and 8 km/h the calculator uses the walking one, like the app: if you jog at those speeds with little incline, it comes up short. With an incline above 11.1%, on the other hand, the walking one already gives more than the running one.

A worked example

Half an hour on the treadmill at 70 kg

Net calories in 30 minutes for a person who weighs 70 kg, with the same math as the calculator.

To get it right

• Don’t hold on to the rail: if you lean on it, you burn less than the calculation says.
• If you change speed or incline, work out each stretch separately and add them up (or use the one you kept up for most of the time).
• Count only the minutes you’re moving and enter your weight today.
• If you walk with your phone in your pocket or with your watch, those steps are already in your daily count: don’t count the session twice, with your steps and with this calculator.
• Walking and running outdoors don’t go here: they count with your steps, as in the app.
• For other activities (cycling, elliptical, swimming…), use the activity calculator.

Frequently asked questions

How many calories do you burn in 30 minutes on a treadmill?

It depends on the speed, the incline and your weight. At 70 kg, from about 70 net kcal walking at 4 km/h on flat ground to about 420 running at 12 km/h. There are more cases in the table above, or work out your own.

Why do the calories more than double from 7.9 to 8 km/h?

Because at 8 km/h the calculator stops assuming you’re walking and starts assuming you’re running, like the app. On flat ground, the ACSM running equation gives twice as much per kilometer as the walking one: for the person in the example, half an hour at 7.9 km/h is about 146 kcal and at 8 km/h, about 296. Those 0.1 km/h don’t cost double: what changes is whether you’re walking or running.

With a steep incline it’s the other way around: the walking equation counts the climb more (1.8 versus 0.9), and above a 11.1 % incline, at the same speed, it gives more than the running one.

What burns more, walking on an incline or running?

It depends on the speed and the incline. According to these equations, at 70 kg, half an hour of walking at 6 km/h on a 10 % incline (about 294 kcal) burns almost the same as half an hour of running at 8 km/h on flat ground (about 280). The best one is the one you can keep up.

Why does the treadmill show a different number?

Treadmills have their own formulas and, if you don’t enter your weight, they don’t know it. Some also count what you’d burn without moving: in the example above, those 40 minutes are about 52 kcal more. And if you hold on to the rail, you burn less than any calculation says: in one study, gripping hard cut the oxygen used by 15 to 21 % (Berling et al., 2006).

Do my steps count too?

If you walk on the treadmill with your phone in your pocket or with your watch, those steps are added to your daily count. If you also log the treadmill, those minutes count twice: keep one of the two. The treadmill takes speed and incline into account; steps don’t.