Cycling Speed From Power Calculator
Estimate flat-road cycling speed from power, weight, and gradient with a simple physics model.
Quick answer: enter your details below and click Estimate Speed — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
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How to use
- Enter your average power in watts.
- Enter rider-plus-bike weight in kilograms.
- Enter the gradient and click Estimate Speed.
About this tool
Enter your average power in watts, total rider-plus-bike weight, and the road gradient. The tool solves a simple resistance model (air drag, rolling resistance, and gravity) for speed. This is an estimate: real speed also depends on position, wind, tyres, and road surface.
Frequently asked questions
Why is speed not proportional to power?
Air drag grows with the cube of speed, so each extra km/h costs more watts than the last.
Does it account for wind?
No. It assumes still air on a smooth road, so a headwind will lower real speed.
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All tools · Read the guide: Cycling Speed From Power Calculator