Calories Burned Calculator
MET values come from the Compendium of Physical Activities, a research catalogue of the measured energy cost of hundreds of activities.
What a MET is
One MET is the energy cost of sitting quietly: by convention, 3.5 ml of oxygen per kilogram of body weight per minute, which works out at roughly 1 kcal per kilogram per hour. An activity rated at 8 METs costs eight times that.
The MET values in the dropdown come from the Compendium of Physical Activities, maintained by Ainsworth and colleagues, which catalogues the measured energy cost of hundreds of activities from laboratory studies. It is the same reference used in published exercise research, which is why these figures are more defensible than the numbers on a gym machine's display.
Gross versus net calories
This distinction is routinely ignored and it matters. The formula above gives gross calories — everything burned during the session, including the energy you would have spent staying alive on the sofa.
For a 75 kg person, 45 minutes of any activity includes about 47 kcal of resting metabolism. If you are counting exercise as something to add on top of your maintenance calories, the net figure is the honest one. This is one reason treadmill displays flatter: they almost always report gross, and they usually assume a heavier default body weight too.
Why real burn varies
MET values are population averages measured in laboratory conditions. Your actual expenditure can differ by 20 % or more:
- Fitness. A trained runner is mechanically more efficient and burns fewer calories covering the same distance at the same pace than an untrained one.
- Body composition. The formula scales with total weight, but fat mass is less metabolically active, so it slightly overestimates for people with high body fat.
- Terrain and conditions. Hills, wind, heat, soft ground and altitude all raise cost substantially. A 5 % gradient roughly doubles the cost of walking.
- Intensity within a category. “Weight training” spans a wide range: heavy compound sets with short rests are nothing like an unhurried machine circuit.
Compensation is the real issue. Studies of exercise programmes consistently find that weight loss falls short of what the calorie arithmetic predicts, because people unconsciously eat more and move less for the rest of the day. Burning 400 kcal in a session is easy; not replacing it is the hard part.
Frequently asked questions
Why is this lower than my fitness tracker says?
Wearables commonly overestimate by 20–50 %, particularly for strength work and anything that is not steady-state cardio. They infer energy expenditure from heart rate, which is a poor proxy when heart rate rises from heat, stress, caffeine or dehydration rather than from work done.
Does afterburn add much?
Less than the marketing suggests. Excess post-exercise oxygen consumption typically adds 6–15 % of the session's cost after genuinely hard training, and close to nothing after moderate work. A 400 kcal session might buy you another 30 kcal.
Do heavier people burn more?
Yes, roughly proportionally — moving more mass costs more energy. That is why weight is in the formula, and why the same walk burns fewer calories as you lose weight.