Cycling Power Estimator

What this tool does

Calculate cycling power from entered performance or equipment data. Steady-state model, no acceleration. CdA, road surface and wind can substantially affect power.

How to use the Cycling Power Estimator

1. Enter or select rider plus bike mass (kg).
2. Enter or select ground speed (km/h).
3. Enter or select headwind (km/h, negative tailwind).
4. Enter or select road gradient (%).
5. Enter or select cda aerodynamic area (m²).
6. Enter or select rolling coefficient.
7. Enter or select air density (kg/m³).
8. Enter or select drivetrain efficiency (%).
9. Read the calculated result; change any measurement to compare alternatives.

Formula

wheel force=mg×(sin(atan(grade/100))+Crr×cos(atan(grade/100)))+0.5ρCdA×airSpeed×abs(airSpeed); crank watts=max(0,force×groundSpeed/efficiency)

mass

Rider plus bike mass (kg)

speed

Ground speed (km/h)

wind

Headwind (km/h, negative tailwind)

grade

Road gradient (%)

cda

CdA aerodynamic area (m²)

crr

Rolling coefficient

density

Air density (kg/m³)

efficiency

Drivetrain efficiency (%)

Steady-state model, no acceleration. CdA, road surface and wind can substantially affect power.

Worked example

For cycling power estimator, the following measurements illustrate the exact method: Rider plus bike mass (kg): 85; Ground speed (km/h): 30; Headwind (km/h, negative tailwind): 0; Road gradient (%): 0; CdA aerodynamic area (m²): 0.32; Rolling coefficient: 0.005; Air density (kg/m³): 1.225; Drivetrain efficiency (%): 97.

Results explained

Estimated crank power (watts)

Estimated crank power (watts) from the formula above. Steady-state model, no acceleration. CdA, road surface and wind can substantially affect power.

Frequently asked questions