Air Resistance Power Calculator

About this calculator

Air resistance power is the wattage a cyclist or runner must produce just to push through the air, calculated as roughly half the air density multiplied by the rider's drag area (CdA — drag coefficient times frontal area) and the cube of airspeed relative to any headwind or tailwind. Because it scales with the cube of speed, air resistance power grows dramatically as speed increases — going twice as fast costs roughly eight times the aero power — which is why it dominates total power output at racing speeds even though it barely matters when riding slowly.

Time trialists, triathletes and track cyclists use aero power estimates to judge whether an equipment change — a skinsuit, a different helmet, an aero position — is worth adopting, since even small reductions in CdA translate into real watts saved at race speed, and pacing strategy for windy courses depends on knowing how much extra power a headwind section will demand compared to a tailwind section.

This calculator takes your speed, drag area (or an estimate from body position), air density and wind conditions, and returns the power in watts needed to overcome air resistance alone.