Cycling Power Calculator
Calculate your cycling power output in watts based on speed, rider and bike weight, road grade, wind resistance, and aerodynamic position. Get your power-to-weight ratio and see how you compare to different performance levels.
What is a good power-to-weight ratio for cycling?
For recreational cyclists: 2-3 W/kg is typical. Fitness/competitive cyclists: 3-4 W/kg. Trained racers: 4-5 W/kg. Elite/professional cyclists: 5-6+ W/kg. Tour de France climbers often exceed 6 W/kg on sustained climbs. These values are for FTP (Functional Threshold Power) - the power sustainable for about an hour.
How is cycling power calculated?
Cycling power = Aerodynamic drag power + Rolling resistance power + Gravitational power. Aero drag = 0.5 × CdA × air density × wind speed² × speed. Rolling resistance = Crr × weight × gravity × speed. Gravity = weight × gravity × slope × speed. All three components add up to total power output in watts.
What is CdA in cycling?
CdA is the coefficient of drag (Cd) multiplied by frontal area (A), measured in m². It represents your aerodynamic resistance. Typical values: Upright position 0.40+, hoods 0.32, drops 0.31, aero position 0.29, time trial 0.25. Lower CdA means less air resistance and higher speeds at the same power.
What affects cycling power requirements most?
At high speeds (>30 km/h), aerodynamic drag dominates (70-90% of power). At low speeds or steep climbs, weight and gravity matter more. On flat terrain at moderate speeds, rolling resistance is significant (10-30%). Wind has a major impact - a 20 km/h headwind can increase power needs by 30-50%.
What is FTP in cycling?
FTP (Functional Threshold Power) is the maximum average power you can sustain for approximately one hour, measured in watts. It's a key metric for training zones and performance tracking. Most cyclists determine FTP through a 20-minute max effort test (multiply average power by 0.95) or a ramp test.
How much power does it take to cycle at 30 km/h?
For a 75kg rider on a 8kg bike in drops position on flat terrain with no wind: approximately 180-200 watts. At 40 km/h: 350-400 watts. Power requirements increase with the cube of speed, so small speed increases require much more power. Adding a 10% climb might require 300-400 watts at 20 km/h.
Does bike weight really matter for cycling power?
Bike weight matters most when climbing - every kg costs about 7-8 watts per 1% grade at 20 km/h. On flat terrain, bike weight has minimal impact (only affects rolling resistance slightly). For a flat 40 km/h ride, a 2kg lighter bike might save only 5-10 watts, but the same weight saving on a 10% climb at 15 km/h saves 15-20 watts.