What this calculator does
The MET system rates activities by how much energy they use relative to sitting still. One MET is resting metabolism; running at 8 km/h is about 8 METs, meaning it uses roughly eight times the resting rate. Multiplying by body weight and duration converts that into calories.
MET values come from published compendiums of measured activity data, and they are population averages. Individual energy cost varies with fitness, technique and body composition: a trained runner is more efficient and burns somewhat less at the same pace than an untrained one.
The formula
One MET corresponds to roughly 3.5 millilitres of oxygen per kilogram of body weight per minute, and each litre of oxygen consumed releases about 5 kilocalories. Combining those constants gives the standard expression: MET × 3.5 × weight ÷ 200 kilocalories per minute.
| Term | Meaning |
|---|---|
| MET | Metabolic equivalent: energy cost relative to rest. |
| 1 MET | Approximately 1 kcal per kilogram of body weight per hour. |
| kJ | Kilojoules. One kilocalorie is 4.184 kilojoules. |
The inputs explained
| Field | What to enter |
|---|---|
| Activity | The activity, with its MET value in brackets. Higher values mean more energy per minute. |
| Weight (kg) | Body weight in kilograms. Energy cost scales directly with body mass, since you are moving that mass. |
| Duration (minutes) | Duration in minutes. Use actual working time rather than total session time: rest between sets is closer to resting metabolism. |
When to use it
Comparing activities honestly
Run the same duration across different activities. The differences are often smaller than expected, and an hour of most exercise sits in the few-hundred-calorie range rather than the thousands.
Understanding why exercise alone is slow going
A 45-minute run burns roughly the energy in a large muffin. Exercise has excellent health benefits, but its direct effect on energy balance is more modest than fitness marketing suggests.
Estimating a full training week
Calculate each session and add them up. That weekly total is what actually influences energy balance, rather than any single workout.
Checking a fitness tracker
Wearables often overestimate energy expenditure, sometimes substantially. The MET calculation gives an independent reference point based on published measurements.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
Calories burned in 45 minutes by activity
A 75 kg person doing 45 minutes of each activity.
| Activity | Calories burned | Per minute | Kilojoules |
|---|---|---|---|
| Walking slow | 148 kcal | 3.3 kcal | 618 kJ |
| Walking brisk | 207 kcal | 4.6 kcal | 865 kJ |
| Gardening | 295 kcal | 6.6 kcal | 1,236 kJ |
| Cycling / weights | 354 kcal | 7.9 kcal | 1,483 kJ |
| Swimming | 413 kcal | 9.2 kcal | 1,730 kJ |
| Running 8 km/h | 473 kcal | 10.5 kcal | 1,977 kJ |
| Running 12 km/h | 679 kcal | 15.1 kcal | 2,842 kJ |
How body weight changes the cost
The same run at a range of body weights.
| Body weight | Calories burned | Per minute | Fat equivalent |
|---|---|---|---|
| 55 kg | 347 kcal | 7.7 kcal | 45 g |
| 65 kg | 410 kcal | 9.1 kcal | 53 g |
| 75 kg | 473 kcal | 10.5 kcal | 61 g |
| 85 kg | 536 kcal | 11.9 kcal | 70 g |
| 95 kg | 599 kcal | 13.3 kcal | 78 g |
| 110 kg | 693 kcal | 15.4 kcal | 90 g |
Duration at a moderate intensity
Moderate cycling over different session lengths.
| Duration | Calories burned | Kilojoules | Fat equivalent |
|---|---|---|---|
| 15 min | 118 kcal | 494 kJ | 15 g |
| 30 min | 236 kcal | 988 kJ | 31 g |
| 45 min | 354 kcal | 1,483 kJ | 46 g |
| 60 min | 473 kcal | 1,977 kJ | 61 g |
| 90 min | 709 kcal | 2,965 kJ | 92 g |
| 120 min | 945 kcal | 3,954 kJ | 123 g |
Questions
How accurate are MET values?
They are population averages drawn from measured data, typically accurate within perhaps 15 to 20 per cent for an individual. Fitness, technique and body composition all shift the real cost.
Should I subtract the calories I would have burned anyway?
Strictly, yes: you would have used roughly 1 MET sitting still. For a 45-minute session that overstates the net figure by around 60 kcal, which matters more for low-intensity activities than for hard ones.
Why does my fitness tracker show a different number?
Trackers use heart rate and movement, which introduce their own errors, and many are known to overestimate. Neither method is a reference standard, so pick one and use it consistently rather than comparing across devices.
What does the fat equivalent figure mean?
It converts the energy burned into grams of body tissue using the 7,700 kcal per kilogram approximation. It is a useful reality check on how much single sessions contribute.
Does exercise raise metabolism afterwards?
Modestly. Post-exercise oxygen consumption adds a small amount, typically well under 10 per cent of the session cost, and mostly after high-intensity work. It is real but far smaller than commonly claimed.
For total daily needs, use the TDEE calculator. For training intensity, see heart rate zones.