Speed From Cadence Calculator
Calculate cycling speed from cadence, chainring, rear cog, tire circumference, and gear ratio, then compare rollout, development, and distance per pedal revolution. This tool is built for practical cycling planning, so it includes the core calculation plus supporting outputs, step-by-step explanation, examples, and guidance for real-world riding conditions.
How cadence, gearing, and tire size create speed
Cycling speed is not created by cadence alone. Speed comes from cadence multiplied by how far the bike travels with each crank revolution. That distance depends on the chainring, rear sprocket, wheel size, and tire circumference. British Cycling explains that cadence is a major part of gear selection because changing gears lets riders keep a workable pedaling rhythm across different terrain; see its gear selection guide.
Formula and example
For example, 90 rpm with a 50×17 gear and 2105 mm tire circumference gives about 33.4 km/h. A smaller rear cog or larger chainring increases speed at the same cadence, while a larger rear cog makes climbing easier but reduces speed per pedal revolution.
What affects real speed
This calculator assumes no tire slip and uses nominal tire circumference. Real outdoor speed also depends on wind, road surface, aerodynamic position, rolling resistance, drafting, and gradient. Use it for gearing comparisons, trainer setup, cadence planning, and checking whether a gear will feel too light or too heavy at your preferred rpm.
Frequently asked questions
- Use the cadence you can realistically hold for the effort. Many road cyclists are comfortable somewhere around 80 to 100 rpm on flat terrain, but climbing, sprinting, fatigue, and riding style can change that. The calculator is most useful when you compare several cadences, such as 70, 85, and 100 rpm, in the same gear.
- Two tires with the same printed size can roll slightly different distances because actual width, rim width, pressure, rider weight, tread, and tire model affect the measured circumference. If you want the most accurate result, roll the bike forward for one wheel revolution and measure the distance on the ground.
- No. Gear inches is an older way to express gearing using an equivalent wheel diameter, while this calculator uses rollout or meters development. Both describe how far a bike travels per pedal revolution, but meters development is usually easier to connect directly to speed.