Cycling Speed from Cadence & Gearing Calculator
Work out road cycling speed from pedaling cadence, chainring and cog teeth, and wheel size — plus gear ratio and metres of development.
How it works
Gear ratio = chainring ÷ cog · Development = ratio × wheel circumference · Speed = cadence × development · km/h = m/min × 60 ÷ 1000
Each full pedal stroke turns the rear wheel by the gear ratio, and each wheel turn rolls forward by its circumference — so development (metres per crank revolution) times cadence gives distance per minute. This is why a higher gear or faster cadence both raise speed, and why the same speed can be held at different cadences by shifting gears. It assumes no freewheeling or slippage, i.e. steady pedaling.
Worked example
A 50-tooth chainring and 15-tooth cog give a ratio of 3.33. With a 2105 mm (2.105 m) wheel, development = 3.33 × 2.105 = 7.02 m. At 90 rpm that is 90 × 7.02 = 631 m/min = 37.9 km/h.
Frequently asked questions
What wheel circumference should I use?
Measure it by rolling the wheel one full turn under your weight, or use a reference: a 700×25c road tyre is about 2105 mm and a 700×28c about 2136 mm. Circumference, not diameter, drives the result.
Does cadence or gearing matter more?
Speed is their product, so both matter equally in the math. In practice riders pick a comfortable cadence (often 80–100 rpm) and change gears to set speed and effort.
Why is my real speed a bit lower?
This is the theoretical no-loss speed. Real riding loses a little to tyre and drivetrain friction, and cadence is rarely perfectly constant, so measured speed runs slightly below the calculated figure.
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This calculator is for educational purposes. Double-check important results before acting on them.