Cycling Power Calculator
Estimate your required cycling power output with real-world cycling physics. Enter your details and see your power, power-to-weight ratio, and recommended training zones.
Calculator Inputs
Understanding Cycling Power and Physics
In cycling, your power output must overcome gravity , rolling resistance , and aerodynamic drag to maintain your speed.
- Gravity (Climbing): Power needed to go uphill increases with gradient and total bike+rider weight.
- Rolling Resistance: Friction between tires and road, affected by tire quality (Crr).
- Aerodynamic Drag: Increases with the square of your speed. Frontal area (A) and drag coefficient (Cd) play key roles.
- Wind: Headwinds increase required power, tailwinds decrease it.
Equations Used:
- Pgravity = (mtotal) × g × v × sin(arctan(gradient/100))
- Proll = (mtotal) × g × v × Crr
- Pair = 0.5 × ρ × Cd × A × (v+vwind)³, where ρ = 1.225 kg/m³ (air at sea level)
Training Zones & Power-to-Weight
- < 2 W/kg: Recovery or recreational (easy)
- 2-2.7 W/kg: Endurance / Base training
- 2.7-3.3 W/kg: Tempo (strong base, long rides)
- 3.3-4 W/kg: Threshold (race effort for trained amateur)
- 4-5 W/kg: Elite amateur/Pro threshold
Values are for sustained power efforts (FTP/threshold). Short-term or sprint power can be higher.
More on Power Calculation Inputs
- Speed: Try your average flat speed, or estimate climb pace for gradients.
- Gradient: For climbs, e.g., 6 for 6%. For downhills, use negative.
- Wind speed: Use positive for headwind, negative for tailwind. Use local weather or estimate.
- Rider/Bike weight: Realistic gear/clothing/shoes/bottles/tools all matter!
- Frontal area & Cd: Lower in aerodynamic position (TT/triathlon), higher upright or for large riders.
- Rolling resistance (Crr): Default road tires on tarmac: 0.003–0.006