How to calculate calories burned
Updated on June 30, 2026 · by Rafael Rossi
Estimating the calories burned in a workout has one simple formula that almost nobody knows — despite it being exactly what runs behind apps and treadmills. It rests on a unit called the MET.
What a MET is
MET stands for Metabolic Equivalent of Task. 1 MET is your energy expenditure at rest: sitting, doing nothing. Every activity is measured as a multiple of that. An 8 MET activity consumes eight times the energy you would have spent sitting still for the same time.
That makes the calculation direct:
calories = MET × weight (kg) × time (hours)
In pounds, divide your weight by 2.205 first — 154 lb is 69.9 kg.
Worked example
Someone at 154 lb running 30 minutes at 5 mph (8.3 METs):
8.3 × 69.9 × 0.5 = 290 kcal
MET table for 30 minutes at 154 lb
| Activity | METs | kcal in 30 min |
|---|---|---|
| Yoga | 2.5 | 87 |
| Walking (3 mph) | 3.5 | 122 |
| Heavy house cleaning | 3.5 | 122 |
| Swimming, moderate | 5.8 | 203 |
| Weight training, vigorous | 6.0 | 210 |
| Recreational soccer | 7.0 | 244 |
| Cycling (12 mph) | 8.0 | 279 |
| Running (5 mph) | 8.3 | 290 |
| Climbing stairs | 8.8 | 307 |
The detail that inflates every number: gross versus net
Here is what apps and treadmills almost never tell you. The MET value already includes your resting metabolism — the 1 MET you would have spent anyway, lying on the couch.
That means the formula returns gross expenditure, not the extra burn caused by exercising. To find what the workout actually added, subtract 1:
extra calories = (MET − 1) × weight × time
In the 30-minute walk above, gross is 122 kcal and the extra is 87 kcal — 29% less. The lighter the activity, the bigger the distortion: in yoga, more than a third of the "burn" is simply you existing.
For anyone tracking intake this matters: eating back the calories an app displays can erase most of the day's deficit.
Body weight is the main multiplier
Notice the formula is linear in weight. Two people running side by side at the same pace for the same time burn very different amounts: 30 minutes at 5 mph costs 248 kcal at 132 lb and 373 kcal at 198 lb.
This is one reason expenditure falls over the course of weight loss: the same workout in a lighter body costs less energy.
How long that food costs you
The most useful way to use the formula is to invert it: instead of asking what a workout burns, ask how much workout a food costs. A slice of pizza at roughly 350 kcal, for someone at 154 lb:
| Activity | Time (gross) | Time (extra burn) |
|---|---|---|
| Running 5 mph | 36 min | 41 min |
| Cycling 12 mph | 38 min | 43 min |
| Weight training | 50 min | 60 min |
| Walking 3 mph | 86 min | 120 min |
The right-hand column is the honest one. Two hours of walking for one slice of pizza explains, better than any lecture, why a calorie deficit is built in the kitchen rather than on the treadmill — without making the walk any less valuable for blood pressure, mood and joints.
What the formula misses
- Individual efficiency. Two people at the same weight and pace can differ by 10% or more through technique, biomechanics and conditioning. An experienced runner spends less for the same distance.
- Terrain and conditions. Hills, sand, wind and heat change the real cost, and MET tables assume flat ground.
- The "afterburn" (EPOC). It is real but small: typically 6% to 15% of the session's cost, not the dramatic figures often advertised. A 300 kcal workout adds perhaps 20 to 45 kcal afterwards.
Add to that the fact that watches and treadmills tend to overestimate, sometimes by 20% to 30%, because they infer from heart rate without knowing your actual efficiency.
Frequently asked questions
Does weight training burn less than running? Per session, almost always yes — because of the effective time under effort. But the comparison misleads: resistance training preserves and builds lean mass, which supports resting metabolism all day, and that effect never shows up in a single session's arithmetic.
Is it better to run faster or longer? For total calories, distance matters more than intensity — the cost is roughly proportional to the miles covered. For cardiorespiratory fitness, intensity plays its own separate role.
Where do I find the MET value for an activity? The Compendium of Physical Activities (Ainsworth et al.) catalogues hundreds of activities with their MET values, and it is the source apps draw from.
Can I lose weight with exercise alone? You can, but it is slow and fragile. An hour of running burns about 580 kcal for someone at 154 lb — replaced by one fast-food meal. Exercise is decisive for health, mood and preserving lean mass; the deficit itself, in practice, is built at the table.
Source: Ainsworth BE et al., Compendium of Physical Activities. Informational content — it does not replace guidance from a fitness or nutrition professional.