Cycling Calories per Kilometre Calculator
Calculate how many calories you burn per kilometre cycling.
Enter your weight, speed, and terrain to get an accurate estimate.
The energy cost of cycling
Cycling is one of the most efficient forms of human movement. A trained cyclist on a road bike at 25 km/h on flat ground burns about 30 to 40 kcal per km, much less than running (about 70 kcal/km) and only modestly more than walking on a per-distance basis. The reason is mechanical: a smooth-spinning bicycle reuses ~95% of pedaling energy as forward motion, with the rest lost to drivetrain friction and tire deformation.
What drives the calorie number
Three factors dominate:
- Body weight (linear effect): heavier riders burn more per km, but only modestly more on flat terrain. Big effect on climbs.
- Speed (cubic effect at high speeds): doubling speed roughly triples the calorie cost per km because aerodynamic drag rises with speed cubed.
- Terrain: hilly riding costs 30 to 50% more calories per km than flat. Mountain riding can double the cost.
The formula
A reasonable working estimate:
kcal/km = body_weight_kg × terrain_factor × speed_factor ÷ 100
Terrain_factor is roughly 1.0 (flat), 1.4 (hilly), 1.8 (mountainous). Speed_factor accounts for aerodynamic drag rising with speed. Different sport-science formulas differ by 10 to 15%, so all numbers are estimates within a few hundred calories on a multi-hour ride.
A reality check
| Rider | Speed | Terrain | kcal/hour | kcal/km |
|---|---|---|---|---|
| 75 kg recreational | 20 km/h | Flat | 470 | 23 |
| 75 kg fit | 30 km/h | Flat | 700 | 23 |
| 75 kg fit | 30 km/h | Hilly | 950 | 32 |
| 90 kg recreational | 25 km/h | Hilly | 850 | 34 |
| 65 kg fit | 35 km/h | Mountain | 1100 | 31 |
Why it matters for nutrition
If you are bonking on long rides, you almost certainly under-eat on the bike. Most recreational cyclists need 30 to 60 g of carbs per hour beyond ~90 minutes of riding. Trained endurance riders push 80 to 120 g/hour using glucose-fructose blends. Use the calorie estimate as a rough fueling target, not a weight-loss accounting tool — your body burns fat preferentially at low intensity and carbs preferentially at high intensity, and a calorie out is not a calorie out from the same fuel tank.