How many calories do you burn during exercise? Calculate based on weight and duration.
Guide to Calorie Burning
What is calorie burning?
Calorie burning is the process by which the body uses energy from food during physical activity and daily tasks. The number of calories burned depends on activity intensity, body weight, duration, and individual metabolism. Every activity, from walking to intense exercise, consumes energy.
MET values
MET (Metabolic Equivalent of Task) is an indicator of physical activity intensity. 1 MET corresponds to resting oxygen consumption. Example values: walking (3.5), running (9-12), swimming (8-11), cycling (7-12), weight training (6-8). The higher the MET, the more calories you burn per unit of time.
How to maximize calorie burning?
- Choose higher intensity activities - HIIT, running, swimming
- Gradually increase activity duration
- Maintain regularity - at least 150 minutes of moderate activity weekly
- Combine strength training with cardio for better results
- Remember to warm up and cool down
Factors affecting calorie burning
Calorie burning is affected by: age (metabolism slows with age), gender (men typically burn more), muscle mass (more muscle = more calories burned), genetics, hormone levels, and whether the body is accustomed to the activity. Even after exercise, the body continues burning calories through EPOC (excess post-exercise oxygen consumption).
The machine says 140 for a walk. The extra burn is 100
Calorie displays report gross energy — everything your body used, including the resting metabolism running anyway. Subtract what you would have burned sitting still and a 30-minute walk drops from 140 kcal to 100. The overstatement is worst where people rely on it most: 40% for walking, only 7% for a hard run.
How it works
- Estimates energy cost from the MET value of an activity, body mass and duration.
- Reports gross and net separately, since only the net figure is extra energy spent.
- Compares activities on the same basis so the trade-off against food is honest.
gross kcal = MET × body mass (kg) × hours resting cost = 1 MET × body mass × hours net kcal = gross − resting MET is a multiple of resting metabolism: 1 MET is sitting still
Worked example
An 80 kg person, 30 minutes of each activity. Resting for the same half hour costs 40 kcal.
- walking 4 km/h (3.5 MET) → gross 140, net 100 — display 40% high
- brisk walk 6 km/h (5.0 MET) → gross 200, net 160 — 25% high
- cycling, moderate (7.5 MET) → gross 300, net 260 — 15% high
- running 10 km/h (9.8 MET) → gross 392, net 352 — 11% high
- running 14 km/h (14.5 MET) → gross 580, net 540 — 7% high
The gap is a fixed 40 kcal, so it matters in proportion to how little you burned. Light activity, where the display is most encouraging, is exactly where it exaggerates most — and intense activity, where nobody needs convincing, is where it is nearly right.
Reading the result
- Against food the net figure is unforgiving. A 400 kcal muffin is 0.57 hours of running at 10 km/h, or 2.00 hours of walking. This is the arithmetic behind the observation that intake is a far larger lever than exercise for most people.
- MET values come from the Compendium of Physical Activities and describe average adults performing an activity at a stated intensity. Individual cost varies with fitness, technique and terrain, so treat any single figure as the centre of a range.
- Cardio machines are typically optimistic beyond the gross-versus-net issue, because they estimate from speed and resistance without knowing your body composition or efficiency. A machine that has not been told your weight is guessing at the largest term in the equation.
- Exercise is worth doing for reasons this calculation does not measure — cardiovascular health, strength, sleep and mood among them. The point of separating gross from net is accuracy about energy, not an argument against training.
Common questions
- Why is the treadmill's number higher than yours?
- Most machines report gross calories, which include the resting metabolism you would have spent anyway. For a 30-minute session that is about 40 kcal for an 80 kg person — a 40% inflation on a walk and a 7% one on a hard run.
- Can I eat back what I burned?
- Only the net figure, and it is smaller than it looks. A 30-minute walk earns roughly 100 kcal, which is a quarter of a large muffin. Treating the gross display as an allowance is one of the more reliable ways to stall progress.