Calculate cycling speed from power output, weight and gradient.
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.
Cycling Speed
Power = ½ρ·CdA·v³ + Crr·m·g·v + m·g·grade·v, solved numerically for speed
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.
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.
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.
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.