Racira Calculator

Cycling Wattage Calculator

Cycling Wattage Calculator

0 = flat · negative = downhill

Advanced Options

CdA ≈ 0.32 drops · 0.40 hoods · 0.28 aero · Crr ≈ 0.004–0.006

Required Power
277 W
3.46 W/kg at 30.0 km/h on 2.0%
Aero Drag
113 W
Rolling
33 W
Gravity
131 W
ComponentValue
Rider + Bike Weight80.0 kg
Speed30.0 km/h
Grade2.0%
Aero Drag Power113 W
Rolling Resistance Power33 W
Gravity Power131 W
Total Power277 W
Power-to-Weight3.46 W/kg

Where the Power Goes

Summary Statistics
Total Power277 W
Power-to-Weight3.46 W/kg
Aero Drag113 W
Rolling Resistance33 W
Gravity131 W
Speed30.0 km/h

About the Cycling Wattage Calculator

Required power is the sum of three resistances: aero drag (½·ρ·CdA·v³), rolling resistance (Crr·m·g·cosθ·v), and gravity on grades (m·g·sinθ·v). Because aero scales with the cube of speed, doubling your speed needs eight times the air-resistance power.

W/kg Matters More Than Watts

On climbs, gravity power is proportional to mass, so the fair comparison is power-to-weight ratio. A 60 kg rider producing 240 W (4.0 W/kg) climbs far faster than an 85 kg rider at 300 W (3.5 W/kg) — this calculator reports both.

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