Cycling Calories from Distance & Grade Calculator
Estimate the calories a bike ride burns from its distance, average gradient, your speed and combined rider-plus-bike weight using a real power model.
How it works
P = (Crr·m·g + m·g·grade + ½·ρ·CdA·v²)·v · kcal = (P ÷ 0.25) · time ÷ 4184
A rider spends energy on three things: rolling resistance, air drag and lifting their mass up the hill. Multiplying the total resisting force by speed gives the mechanical power at the pedals, and dividing by the body's ~25% gross efficiency converts that to the metabolic energy actually burned. Gradient dominates on climbs, while air drag (which grows with the square of speed) dominates on the flat.
Worked example
At 25 km/h (6.94 m/s), 82 kg, a 2% grade and Crr 0.005, the force is 4.0 N rolling + 16.1 N gravity + 10.3 N drag = 30.4 N. Power is 30.4 × 6.94 ≈ 211 W. Over 40 km (1.6 h) that is 211 ÷ 0.25 × 5760 s ≈ 4.86 MJ, or about 1,160 kcal.
Frequently asked questions
Why does grade matter so much?
Climbing adds a gravity force of mass × g × grade that is spent purely on gaining height. On a 6–8% climb this term is several times larger than rolling resistance and air drag combined, which is why the same distance uphill burns far more than on the flat.
Does coasting downhill burn calories back?
No — you cannot recover energy by descending, so this calculator ignores negative work on downhills. A rolling descent burns close to your resting rate, not a negative amount.
How accurate is the 25% efficiency figure?
Trained cyclists convert roughly 22–26% of metabolic energy into pedal work; 25% is a good central estimate. Individual efficiency, drivetrain losses and wind make any calorie figure an estimate within about ±15%.
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This calculator is for educational purposes. Double-check important results before acting on them.