Cycling Speed Calculator
Calculate cycling speed from power output, weight and gradient.
About Cycling Speed Calculator
The equation cannot be solved algebraically for speed because of the cubic drag term, so it is solved numerically. On the flat drag dominates, while on climbs gravity does. This is why aerodynamic equipment helps on flat courses and weight matters on hilly ones, and why the same power gives very different speeds on each.
Formula
Cycling Speed
Power = ½ρ·CdA·v³ + Crr·m·g·v + m·g·grade·v, solved numerically for speed
- cubic drag term
- Aerodynamic power rises with the cube of speed
- gravity term
- Dominates on climbs, where aerodynamics matters little
Worked example
With the default values below, Cycling Speed Calculator returns Estimated Speed of 34.742. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Power outputminimum 1 W
- 220 W
- Rider weightaccepts 20–200 kg
- 72 kg
- Bike weightaccepts 3–30 kg
- 9 kg
- Gradientaccepts -20–25 %
- 0 %
- Drag areaaccepts 0.15–0.8 m2
- 0.32 m2
Results
- Estimated Speed
- 34.742 km/h
- Estimated Speed
- 9.6505 m/s
- Power Overcoming Gravity
- 0.0 W
- Power Overcoming Air Resistance
- 176.2 W
- Power to Weight Ratio
- 3.056 W/kg
Step by step
- 1Values used
- 2Cycling Speed
- 3Estimated Speed= 34.742 km/h
- 4Estimated Speed= 9.6505 m/s
- 5Power Overcoming Gravity= 0.0 W
- 6Power Overcoming Air Resistance= 176.2 W
- 7Power to Weight Ratio= 3.056 W/kg
Assumptions and limits
- The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- These figures are population-average estimates for training and recreational planning only and are not medical advice. Individual responses vary widely. Consult a qualified health professional before starting or significantly changing an exercise, supplement or nutrition programme, particularly if you have any medical condition.
- This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
These figures are population-average estimates for training and recreational planning only and are not medical advice. Individual responses vary widely. Consult a qualified health professional before starting or significantly changing an exercise, supplement or nutrition programme, particularly if you have any medical condition.
Frequently Asked Questions
How is Cycling Speed calculated?
Power = ½ρ·CdA·v³ + Crr·m·g·v + m·g·grade·v, solved numerically for speed The equation cannot be solved algebraically for speed because of the cubic drag term, so it is solved numerically. On the flat drag dominates, while on climbs gravity does.
Why does Cycling Speed matter?
This is why aerodynamic equipment helps on flat courses and weight matters on hilly ones, and why the same power gives very different speeds on each.
What values do I need to enter?
This calculator takes 5 inputs: Power output, Rider weight, Bike weight, Gradient, Drag area. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.