Cycling Power Calculator
Estimate the power in watts needed to ride at a given speed on a given gradient. Enter your combined rider-and-bike weight, your speed and the grade.
Estimated power
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How Cycling Power Is Estimated
The power you need at the pedals is the sum of three resistances, divided by drivetrain efficiency:
- Rolling resistance — tyres against the road:
Crr × mass × g - Air resistance — grows with the square of speed:
½ × ρ × CdA × v² - Climbing — lifting your weight up the grade:
mass × g × sin(θ)
This calculator assumes sensible defaults: rolling coefficient 0.005, drag area (CdA) 0.32 m², air density 1.225 kg/m³ and 97% drivetrain efficiency. Real numbers vary with tyres, position, wind and altitude, so treat the result as a solid ballpark.
What the Breakdown Tells You
At low speeds on a climb, climbing power dominates. On the flat at speed, air resistance takes over — which is why aerodynamics matter so much for fast riders. Rolling resistance is small but constant.
Plan the Climb
Know the gradient before you ride it. Trace your route and read the grade from the elevation profile, or plan the whole ride with the cycling route planner.
Get Distance Tool
Download Distance Tool for iOS and start measuring in seconds.
