How many calories does running burn?
Running costs roughly 1 kcal per kilogram of bodyweight per kilometre. That is very nearly the whole calculator: your weight in kilograms is your burn per kilometre in kilocalories. A 70 kg (155 lb) runner spends about 70 kcal per kilometre, 113 kcal per mile, and 350 kcal over a 5 km (3.1 miles).
| Bodyweight | Per kilometre | Per mile | 5 km (3.1 mi) | 10 km (6.2 mi) | |
|---|---|---|---|---|---|
| 55 kg | 120 lb | ~55 kcal | ~88 kcal | ~275 kcal | ~550 kcal |
| 70 kg | 155 lb | ~70 kcal | ~113 kcal | ~350 kcal | ~700 kcal |
| 85 kg | 185 lb | ~85 kcal | ~137 kcal | ~425 kcal | ~850 kcal |
| 100 kg | 220 lb | ~100 kcal | ~161 kcal | ~500 kcal | ~1,000 kcal |
In imperial terms, about 0.73 kcal per pound per mile. Notice what is missing from that table: pace.
A fast 5k and a slow 5k burn about the same
This is the part that surprises people, and it follows from where the energy actually goes. Most of the bill is paid supporting your bodyweight and swinging your limbs through each stride. The cost per stride is roughly fixed, and the number of strides in a kilometre changes far less with speed than you would guess — so the cost of the kilometre barely changes either.
Running faster does not make the kilometre more expensive. It compresses it in time, which raises the rate:
- 70 kg (155 lb), 5 km in 20 minutes: ~350 kcal, at ~17 kcal/min
- 70 kg (155 lb), 5 km in 35 minutes: ~350 kcal, at ~10 kcal/min
If anything the slow run posts the larger total, because it folds in fifteen more minutes of resting burn — about 18 kcal — that would have happened on the sofa. That is the same gross-versus-net distinction that inflates step-count estimates: the clock bills you whether you run or not.
The flatness has limits. Air resistance adds a few percent at genuinely quick speeds, and a very slow shuffle is slightly less economical per kilometre than a comfortable jog. Neither is anywhere near the twofold difference people imagine between an easy run and a hard one over the same route.
Running economy, and an awkward implication
That 1 kcal/kg/km is an average with real spread around it. Trained runners are measurably more economical than beginners at the same speed — better elastic return from tendons, less wasted vertical and lateral motion, less braking at footstrike. The gap between a novice and a well-trained runner is commonly 5–15%, and it is why two people side by side on the same route burn different amounts.
Which produces uncomfortable arithmetic for anyone running to lose weight. Two things happen as the plan works:
- You get fitter, so each kilometre costs a little less.
- You get lighter, so each kilometre costs proportionally less. Go from 85 kg to 75 kg (185 lb to 165 lb) and your 5 km falls from ~425 to ~375 kcal.
The run that cost 425 kcal in January costs under 375 in June for identical effort. Nothing has gone wrong — the denominator moved. It is one of the ordinary reasons progress slows, and it argues for recalculating against your maintenance calories every few kilograms rather than running further to chase the old figure.
The afterburn is real, and small
EPOC — excess post-exercise oxygen consumption — is the elevated metabolic rate after a session while the body restocks oxygen, clears metabolites and repairs tissue. It exists. It is also routinely oversold.
For a typical endurance run, EPOC comes to something in the region of 5–10% of the session’s cost. On a 350 kcal run that is roughly 20 to 35 kcal — a mouthful of banana. Very long or very hard sessions push it higher, into the low hundreds, but that is not a Tuesday evening 5k. Anything promising hours of meaningful afterburn from a moderate run is selling something.
Distance beats heart rate as a calculator
For running specifically, distance × bodyweight is a better estimator than a heart-rate model. The physics is simple and the input is measured rather than inferred, whereas heart rate at a fixed pace drifts with heat, caffeine, sleep and accumulated fatigue. Watches are best read as consistent rather than correct, which is the fuller argument in how accurate Apple Watch calorie tracking is.
Two practical notes. Treadmill displays usually report gross energy and often run optimistic, so do not expect them to agree with the table above. And never log a run by hand that your watch already recorded — the same kilometres then count twice.
Finally, keep the figure in proportion. Three 5 km runs a week is roughly 1,050 kcal: real, worth having, and smaller than a single loose weekend. Running is a good habit and a poor eraser, and the deficit itself is mostly decided at the table — which is why how big your deficit should be matters more than how fast you ran.
General information, not medical advice.