Calorie Burn Calculator

What a MET is

One MET is your resting metabolic rate — roughly 3.5 ml of oxygen per kg of bodyweight per minute, or about 1 kcal per kg per hour. An activity at 6 METs costs six times your resting rate.

The arithmetic is: kcal/min = MET × 3.5 × kg ÷ 200.

MET values come from the compendium of physical activities, which measured oxygen consumption across hundreds of activities. They are group averages, and the variation within an activity is large — "vigorous weight training" covers a very wide range of actual effort.

Gross versus net

Almost every calorie calculator reports gross burn — everything your body used during the session, including the resting metabolism you would have burned sitting on the sofa.

Net subtracts that resting cost. It is the genuinely extra energy the session cost you, and it is the number to use if you are adding exercise calories back into your intake. Using gross double-counts your resting metabolism, which is one of the most common reasons people eat back more than they burned.

For a 45-minute walk the difference is around 60 kcal. For a long session it is considerably more.

Why exercise is a poor fat-loss lever on its own

An hour of vigorous weight training at 80 kg burns around 500 kcal gross, 420 net. That is real, and it is roughly two slices of pizza. Meanwhile a 400 kcal daily deficit from food requires no time at all.

This is not an argument against training — resistance training is what keeps the muscle while you lose fat, which is the entire point. It is an argument against using exercise as the primary means of creating a deficit, and against eating back gross calorie estimates from a wearable.