Calories Burned Calculator

How calories burned is calculated

Every figure on this page comes from one number attached to the activity you picked: its MET value. MET stands for metabolic equivalent of task, and it is the unit exercise physiology uses to describe how hard something is relative to doing nothing at all.

One MET is defined as resting metabolic rate: the consumption of 3.5 millilitres of oxygen per kilogram of body weight per minute. That is roughly what your body uses sitting quietly in a chair. An activity rated at 6 METs costs six times that rate, so it consumes about 21 millilitres of oxygen per kilogram per minute for as long as you keep going. The scale is deliberately simple: it lets a single number describe the intensity of an activity independently of who is performing it.

Turning oxygen into calories takes one more step. Burning a litre of oxygen releases approximately 5 kilocalories of energy, and that constant is what the division by 200 in the equation below encodes. Multiply METs by 3.5 to get millilitres of oxygen per kilogram per minute, multiply by body weight in kilograms to get millilitres per minute, then divide by 200 to convert millilitres of oxygen into kilocalories per minute. Multiply by the number of minutes and you have the session total.

Two things follow from the shape of that equation, and both matter when you read the result. Energy cost scales directly with body weight, so a 100 kg person burns roughly 43 per cent more than a 70 kg person doing exactly the same thing for the same length of time. And cost scales directly with time, so intensity and duration are interchangeable in the arithmetic even though they are not interchangeable in your body. Twenty minutes of running and forty minutes of brisk walking come out close on this page; they are not the same training stimulus.

Source: Ainsworth BE, Haskell WL, Herrmann SD, et al. 2011 Compendium of Physical Activities: a second update of codes and MET values, Med Sci Sports Exerc 43:1575–1581 (2011).

MET values across common activities

These are the values this calculator uses, drawn from the Compendium. They are worth reading as a rough map of intensity rather than as precise costs. Notice how wide the bands are within a single activity: walking spans 2.8 to 5.0 METs depending only on pace, and running spans 8.3 to 14.5. Intensity, not activity type, is what actually drives the number.

Climbing stairs at 8.0 METs is worth a second look. It matches basketball and moderate cycling, and beats most gym classes. Activities that move your body weight against gravity are expensive, which is why the cheapest available intensity increase for most people is finding a hill or a staircase rather than buying equipment.

Where this number misleads

MET values are population averages measured in laboratories, often on small samples of healthy young adults performing an activity under controlled conditions. Your result is that average applied to your body weight. It knows nothing else about you, and there are several well-documented ways the estimate drifts from reality.

It ignores everything except your weight

Fitness level, technique and efficiency are absent from the equation. A trained swimmer and a beginner covering the same distance in the same time do not spend the same energy. The beginner spends considerably more fighting the water. Trained runners are more economical than untrained ones at identical speeds. Terrain, gradient, wind and altitude are all missing too, and each of them can move the true cost of an outdoor session by 20 per cent or more.

The linear weight assumption breaks at the extremes

Because cost scales directly with body mass, the equation implicitly assumes you are carrying your whole body weight through the activity. For walking, running and stair climbing that is broadly true. For cycling and swimming it is not: the bike and the water support most of the load, so the equation overstates energy cost for very heavy people in those activities. If you are well above average weight and your training is non-weight-bearing, treat the figure as an upper bound.

It assumes steady-state effort throughout

A MET value describes a sustained intensity. Real sessions rarely look like that. Interval training alternates hard and easy blocks, strength work is mostly rest punctuated by short efforts, and stop-start sports like football or tennis have you standing still for a meaningful share of the clock. Applying a single average intensity to the full duration models these badly in both directions, and the calculator has no way to know which way your session leaned.

The headline includes the calories you would have burned anyway

This is the correction almost no calculator makes, and it is the most important one on the page. The MET equation returns gross energy expenditure: the total your body used during the session, which includes the resting metabolism that was running regardless. If you had spent that hour on the sofa you would still have burned roughly one MET-hour of energy. The genuinely extra cost of training is therefore lower than the headline figure, by about one MET's worth for every hour you exercised. For a 70 kg adult that is around 74 kcal an hour, which is why the result panel shows a net figure alongside the gross one.

Machines and wearables inflate the number further

If your treadmill or watch reports a higher figure than this page, do not assume it knows something extra. Validation studies comparing consumer wearables and gym cardio equipment against laboratory gas analysis have repeatedly found energy expenditure overstated by roughly 15 to 30 per cent. Heart-rate-based estimates hold up reasonably for steady cardio and fall apart for strength and interval work, where heart rate stops tracking oxygen uptake closely. Equipment that does not know your weight is guessing at the largest single term in the equation.

Exercise calories are easy to overestimate and easy to eat back

Put those errors together and the practical risk is clear. A session credited at 600 kcal might really have cost 400 gross and 330 net of resting metabolism. A post-workout smoothie can undo all of it in four minutes. A kilogram of body fat stores roughly 7,700 kcal, which means a moderate daily session takes a fortnight or more to account for one kilogram even before appetite responds. And appetite usually does respond. This is why exercise is a weak lever for fat loss relative to intake, despite being one of the strongest interventions available for cardiovascular health, insulin sensitivity, mood and preserving muscle while you diet. Train for those reasons. Use food intake to control body weight.

Using the number sensibly

The most common mistake with a calories-burned figure is adding it to a daily maintenance estimate that already contains it. If you have used our TDEE calculator and selected an activity level like "moderately active: moderate exercise 3–5 days a week", that multiplier has already priced in your habitual training. Adding today's session on top counts the same exercise twice, and the error compounds every day you do it.

There are two defensible methods, and the only rule is not to mix them. The first is to set your TDEE using the multiplier that honestly describes your typical week and then leave it alone, never adding individual sessions, treating the daily figure as an average across training and rest days. This is simpler, more stable, and what most dietitians use. The second is to set your TDEE at the sedentary multiplier, which covers basal metabolism plus the incidental movement of ordinary life, and then add each session's calories on the days you actually train. This gives you a genuinely different intake target on training and rest days, which some people prefer for appetite reasons. If you take that route, add the net figure rather than the gross one, because sedentary already accounts for the resting energy underneath your session.

Whichever route you pick, this figure is best used for comparison rather than accounting. It is reliable at telling you that thirty minutes of running costs meaningfully more than thirty minutes of yoga, and that raising your walking pace from slow to brisk nearly doubles the cost of a walk. It is far less reliable at telling you the exact number to enter in a food diary. If you want to plan intensity directly, our heart rate zone calculator works from your own measured response rather than a population average, and our macro calculator turns a daily calorie target into protein, carbohydrate and fat.

Common questions