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Wind Resistance Calculator — Headwind & Tailwind Effect
Calculate the effect of headwind and tailwind on power requirements.
How We Calculate This
Wind Effect on Power
The effective air speed changes with wind:
- Headwind: effective air speed = riding speed + wind speed
- Tailwind: effective air speed = riding speed - wind speed
- Crosswind: uses vector sum approximation
Drag power = 0.5 x air_density x CdA x effective_air_speed² x riding_speed
Frequently Asked Questions
A 15 km/h headwind at 30 km/h riding speed roughly doubles the aerodynamic power needed to hold your speed. For a typical road CdA of 0.32 that is about +140W; the range is roughly 110-180W depending on your CdA (lower if you are aero, higher if upright).
No. Due to the cubic relationship between speed and drag, headwinds cost more power than tailwinds save. An out-and-back ride in wind is always slower than in calm conditions.
Crosswind creates a partial headwind component. The effect depends on the angle; this calculator uses a simplified model for cross-wind estimation.
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Last updated: February 2026
All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.