Cycling Wattage Calculator — Power Required to Ride
Enter your total mass, speed, road gradient, drag area (CdA) and rolling resistance to calculate the watts you must produce at the pedals — broken down into aerodynamic, gravity, rolling and drivetrain components.
kg
km/h
%
m²
%
Total watts at the pedals to maintain the entered speed on the given gradient
- 1
Speed in m/s
30 ÷ 3.6 = 8.333 m/s - 2
Aerodynamic drag power: ½ × ρ × CdA × v³
0.5 × 1.225 × 0.32 × 8.333³ = 113.4 WAir resistance grows with the cube of speed — dominant above ~20 km/h on flat roads. - 3
Gravity power: m × g × v × sin(grade)
80 × 9.81 × 8.333 × sin(0%) = 0 W - 4
Rolling resistance power: m × g × Crr × v
80 × 9.81 × 0.004 × 8.333 = 26.2 W - 5
Total power at pedals ÷ drivetrain efficiency
(113.4 + 0 + 26.2) ÷ 0.97 = 143.9
How does this calculator work?
Cycling power = (½ρCdAv³ + mgv·sin θ + mgCrr·v·cos θ) ÷ drivetrain efficiency. Aerodynamic drag grows with v³ and dominates above ~20 km/h on flat roads; gravity dominates on climbs. Enter mass, speed, grade, CdA and Crr to get total watts and a breakdown of each component.
Formula
How this is calculated
Cycling power is the sum of three physical resistances plus drivetrain friction. Aerodynamic drag (P_aero = ½ × ρ × CdA × v³) dominates at higher speeds — it grows with the cube of speed, so doubling speed requires eight times the power to overcome air resistance alone. The drag area CdA bundles the frontal area and drag coefficient; a tuck position (CdA ≈ 0.25 m²) is far more efficient than sitting upright (CdA ≈ 0.45 m²).
Gravity power (P_gravity = m × g × v × sin(grade_angle)) is proportional to speed and gradient — on a 5% climb, a 75 kg rider pushing 30 km/h needs about 306 W just to climb. Rolling resistance power (P_rolling = m × g × Crr × v × cos(grade_angle)) is the energy consumed by tire deformation; a good road tire (Crr ≈ 0.003) adds only a small fraction compared to air drag on flat roads.
Drivetrain efficiency accounts for energy lost in the chain and gears — typically 97% for a clean drivetrain, so the rider must put out ~3% more power at the pedals than arrives at the rear wheel. Air density is set to 1.225 kg/m³ (sea level, 15°C); riders at altitude or in high heat will find actual power slightly different.
Frequently asked questions
Recreational cyclists average 2–3 W/kg at threshold; amateur racers 3–4 W/kg; elite road cyclists 5–6 W/kg; Tour de France contenders often exceed 6 W/kg for a 20-minute climb. Use the W/kg figure this calculator produces to compare with benchmarks for your discipline.
Aerodynamic drag scales with v³, so at 40 km/h it is by far the largest resistance. Reducing CdA from 0.36 (hoods) to 0.25 (full TT tuck) saves roughly 50–60 W at that speed — more than most riders can produce through additional fitness.
Yes. At altitude, air density ρ is lower, so aerodynamic drag is reduced — professional climbs at 2 000–3 000 m involve 15–25% less drag power than at sea level. This calculator uses sea-level air density (1.225 kg/m³); for altitude estimates, reduce CdA proportionally to the density ratio.
Also known as
TG we-Calculate Editorial Team. (2026). Cycling Wattage Calculator — Power Required to Ride [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/cycling-wattage-calculator
TG we-Calculate Editorial Team. "Cycling Wattage Calculator — Power Required to Ride." TG we-Calculate. 2026. https://we-calculate.com/calculator/cycling-wattage-calculator.
TG we-Calculate Editorial Team, "Cycling Wattage Calculator — Power Required to Ride," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/cycling-wattage-calculator
@misc{wecalculate_cycling_wattage_calculator, title = {Cycling Wattage Calculator — Power Required to Ride}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/cycling-wattage-calculator}}, year = {2026}, note = {TG we-Calculate} }
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