Bike Cadence & Speed Calculator

FAQ

How do you calculate bike speed from cadence?

Speed (km/h) = cadence (rpm) × development × 60 ÷ 1000, where development = (chainring teeth ÷ rear cog teeth) × wheel circumference in meters. Example: 90 rpm with 50/15 gears on a 700×25c wheel (2.105 m) gives 7.02 m development, so 90 × 7.0167 × 60 ÷ 1000 ≈ 37.89 km/h (23.54 mph).

What is gear development?

Development is the distance your bike travels with one full turn of the cranks. It equals the gear ratio (chainring ÷ cog) times the wheel circumference. This calculator shows it for every result so you can compare gears.

How do I find the cadence I need for a target speed?

Switch to the “Speed → Cadence” tab and enter your target speed. The calculator inverts the formula: cadence (rpm) = speed (km/h) × 1000 ÷ (development × 60). For example, 37.89 km/h with 50/15 gears on a 700×25c wheel needs 90.0 rpm.

Which wheel circumference should I use?

Use the preset that matches your wheel: 700×25c = 2.105 m, 26″ = 2.070 m, 29″ = 2.280 m. For the most accurate result, choose Custom and enter your measured rollout: mark the tire, roll the bike exactly one wheel revolution, and measure the distance in meters.

Does the calculator show speed in mph?

Yes. Every cadence-to-speed result shows both km/h and mph (1 km/h = 0.621371 mph). The target-speed input is in km/h.

What cadence should I aim for?

Many road cyclists aim for roughly 80–100 rpm on flat terrain, with lower cadences common on climbs and higher cadences in sprints. There is no single correct value — use this tool to see what speed your preferred cadence produces in each gear.

Why does my speed change in a different gear at the same cadence?

Because development changes. A bigger chainring or smaller rear cog raises the gear ratio, so each crank revolution moves the bike further. At a fixed cadence, more meters per revolution means more speed — and more effort per pedal stroke.