Cycling Speed from Power Calculator

About this calculator

This calculation solves the cycling power-balance equation for speed: the watts you produce must overcome aerodynamic drag (shaped by your frontal area and air density), rolling resistance from tires and road surface, and gravity on any climb, and once you fix those resistances the equation can be rearranged to find the speed a given power output will actually sustain. It is the same physics used by power-based pacing tools, just applied to answer "how fast" rather than "how many watts."

Cyclists pacing a climb, time trial or flat ride, and coaches building race strategies around a rider's known power numbers, use this to convert a target or sustainable wattage into the speed and finish time they can realistically expect, rather than relying on feel or flat-ground assumptions that fall apart once grade or wind change.

This calculator takes your power output along with the ride conditions and returns the speed those watts will produce.