Running Power Estimate Calculator

About this calculator

Running power in watts is modeled as the sum of three physical costs: the power to move your body mass forward on flat ground at your pace, the extra power needed to lift your mass against gravity on any uphill gradient (which becomes negative, i.e. assistive, on downhills), and the power spent overcoming air resistance, which grows with the cube of your speed relative to the wind and is worsened by a headwind or reduced by a tailwind. Dividing total power by body weight gives watts per kilogram, the metric that lets runners of different sizes compare effort level directly, the same way cyclists do.

Runners who train with power meters — footpods or watch-based sensors — use this kind of breakdown to pace evenly across varying terrain and wind conditions, since power stays a more stable effort signal on hills and in wind than pace or heart rate does. It's also useful without a power meter at all, as a way to sanity-check a sensor's readings or to estimate the power cost of a planned route before running it.

This calculator takes your weight, running speed, gradient and headwind or tailwind, and returns total power in watts and watts per kilogram, split into the flat, climbing and air-resistance components.