Cycling Power Estimate Calculator
Estimate the power needed to hold a speed on the road from the physics of gravity, rolling resistance and air drag.
How to use
- Enter rider and bike weights.
- Enter your speed and the road gradient.
- Choose your riding position and read the estimated watts.
Note
Model: power = (gravity + rolling resistance + air drag) x speed, divided by 0.97 for drivetrain losses. Air density 1.225 kg/m3 and rolling coefficient 0.005 are assumed. Wind, road surface and drafting change real power a lot. Estimate only — not medical advice.
Frequently Asked Questions (FAQ)
What does the Cycling Power Estimate Calculator do?
It estimates the watts needed to ride at a given speed from rider and bike weight, road gradient and riding position.
What inputs does it need?
Rider weight, bike and kit weight, speed in km per hour, gradient percent and riding position.
Which riding positions can I choose?
Relaxed upright, on the hoods, in the drops, or aero/triathlon bars. A more aero position lowers air drag, so the same speed needs fewer watts.
Is the watt number exact?
No, it is an estimate from a physics model. Real power also depends on wind, tyres, road surface and your exact body position.