Cycling Power Calculator
Estimate your cycling power output in watts from speed, weight, gradient, and wind.
Useful for training and performance analysis.
Cycling power output (measured in watts) represents the mechanical work a rider produces per second. It is the gold standard metric for measuring cycling performance and effort — far more precise than speed alone, which varies with wind, gradient, and terrain.
The total power required to ride a bicycle at a given speed is the sum of several resistive forces:
Rolling resistance power = Crr × M × g × v Where Crr is the rolling resistance coefficient (≈ 0.004 for road tires, 0.008 for gravel), M is total mass (rider + bike) in kg, g is 9.81 m/s², and v is speed in m/s.
Gradient power = M × g × sin(θ) × v Where θ is the road gradient as a decimal (e.g. 5% = 0.05). This term dominates on climbs.
Aerodynamic drag power = 0.5 × ρ × CdA × (v + v_wind)² × v Where ρ is air density (≈ 1.225 kg/m³ at sea level), CdA is the drag coefficient × frontal area (≈ 0.3 for a road cyclist in drop bars), and v_wind is headwind speed.
Total power = Sum of all three components.
This calculator uses a simplified model assuming sea-level air density and typical road-cycling CdA. In practice, power meters measure this directly — but this estimate is accurate to within 5–10% for most riders.
Reference values: A recreational cyclist averages 150–200W. A trained club rider sustains 250–300W. A professional climber may average 400–450W for 20+ minutes. Functional Threshold Power (FTP) — the power you can sustain for one hour — is the standard training baseline.
Example: A 75 kg rider on a 9 kg bike (84 kg total), riding at 30 km/h on flat ground with no wind: rolling resistance ≈ 33W, aero drag ≈ 116W, gradient ≈ 0W → total ≈ 149W.