Calculadora de Potencia em Ciclismo (Watts)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
P = (m·g·sin(θ) + Crr·m·g + 0,5·CdA·ρ·v²) × v
About this calculator
This calculator estimates the power in watts required for a cyclist to ride a bicycle, considering road gradient, rolling resistance, and aerodynamic drag. The calculation uses the formula P = (m·g·sin(θ) + Crr·m·g + 0.5·CdA·ρ·v²) × v, where m is total mass (cyclist + bike), g is gravity, θ is the gradient angle, Crr is the coefficient of rolling resistance, CdA is the drag area, ρ is air density, and v is speed.
How to use: enter total weight (cyclist + bike) in kg, speed in km/h, gradient in percent (positive for uphill, negative for downhill), rolling resistance coefficient (typical 0.004 for road tires), CdA coefficient (typical 0.4 for normal position, 0.3 for aerodynamic), and air density (default 1.225 kg/m³ at sea level). The calculator converts gradient to radians and outputs power in watts.
When to use: ideal for cyclists planning workouts, comparing performance under different conditions, or estimating power needed for a given route. For example, a 70 kg cyclist with a 10 kg bike climbing a 5% grade at 20 km/h needs about 200 W, depending on aerodynamic parameters. It helps understand the impact of weight, aerodynamics, and gradient on effort.
Cautions: the formula is a simplification and does not consider factors like crosswind, drivetrain efficiency, temperature, or altitude variations. CdA and Crr are approximations; precise values require wind tunnel or roller testing. Air density varies with altitude and temperature; adjust as needed. Use the calculator as a reference, not an absolute value.
Frequently asked questions
What does a result of 250 watts mean?
250 watts is the power you need to generate while pedaling to maintain the given speed and gradient. Amateur cyclists sustain about 150-250 W at moderate effort, while professionals can exceed 400 W.
What is a typical CdA value for a road bike?
For normal position, CdA ≈ 0.4 m²; for aerodynamic position (hands on drops), ≈ 0.3 m²; with aerodynamic equipment, it can reach 0.25 m².
How does a negative gradient (descent) affect the result?
On descents, power can be negative, indicating gravity provides energy. You may need to brake instead of pedal. The calculator outputs negative power in that case.
Why does the result differ from my power meter?
The calculator uses approximate Crr and CdA values. Real power meters account for mechanical losses and specific conditions. Use the tool for estimates, not to replace measurements.
Should I consider bike weight separately?
Yes, total mass (cyclist + bike) must be entered. A heavier bike increases required power, especially on climbs.