Calculator
Calories burned cycling
How many calories a ride burns, from your average power, the kilojoules on your bike computer, or a planned TSS and your FTP. Add your details to see the calories on top of what you'd have burned resting.
1,291 kcal
gross · 645 kcal/hr
- Work done
- 1,296 kJ
- kcal per kJ
- × 0.996 at 24.0%
Add weight, height, and age to see the net figure — what to add to a day's calories.
How calories burned cycling are worked out
A power meter measures the work you put into the pedals, in kilojoules: average watts × seconds ÷ 1,000. Your body spends more energy than that, because muscles turn only about a quarter of it into pedal force — the rest is heat. That fraction is your gross efficiency, and dividing by it (and by 4.184, the kJ in a kcal) gives the calories you burned:
kcal = kJ ÷ (efficiency × 4.184)
Why kJ and kcal read almost the same
At 24% efficiency, typical for trained cyclists, 1 ÷ (0.24 × 4.184) = 0.996. So 1 kJ of work costs almost exactly 1 kcal — which is why bike computers show the two as the same number. It's a coincidence of physiology, not a rule: efficiency varies from about 20% to 25% between riders, and the factor moves with it.
| Efficiency | kcal per kJ | 1,000 kJ ride |
|---|---|---|
| 20% | 1.195 | 1,195 kcal |
| 22% | 1.086 | 1,086 kcal |
| 24% | 0.996 | 996 kcal |
| 25% | 0.956 | 956 kcal |
Calories burned cycling by power and time
Gross calories at 24% efficiency, by average power and ride length.
| Avg power | 1 h | 2 h | 3 h | 4 h |
|---|---|---|---|---|
| 125 W | 448 | 896 | 1,344 | 1,793 |
| 150 W | 538 | 1,076 | 1,613 | 2,151 |
| 200 W | 717 | 1,434 | 2,151 | 2,868 |
| 250 W | 896 | 1,793 | 2,689 | 3,585 |
| 300 W | 1,076 | 2,151 | 3,227 | 4,302 |
Gross vs net calories
The gross figure includes the energy you'd have burned anyway, sitting still, for the length of the ride — roughly 60–90 kcal an hour. If your daily calorie target already counts your resting metabolism, adding the gross figure counts those hours twice. Subtract resting energy (your BMR × hours ÷ 24) and add the net figure instead. The calculator estimates BMR with the Mifflin-St Jeor equation.
Planning from TSS and FTP
For a ride you haven't done yet, there's no power file — but there's usually a planned training load. Since TSS = hours × IF² × 100, the plan's TSS gives its intensity factor, IF × FTP gives average power, and the rest follows. This assumes steady power; an interval session reads 5–10% low, because its normalized power runs above its average.
Without a power meter
Heart rate is the usual fallback, and a much rougher one: expect errors of 20–30%, worst in heat, dehydration, and long rides, when heart rate drifts up while the work doesn't. Fuelwright uses the Keytel heart-rate equations when there's no power, and perceived effort when there's neither.
Running and swimming
Power doesn't carry over to other sports. A run costs about 1 kcal per kg of body weight per km at almost any pace, so a 70 kg runner burns about 700 kcal over 10 km. Swimming depends so much on technique that pace says little, so Fuelwright works from how hard the swim is against your own threshold.