Bike Cadence and Speed Calculator

Your speed on a bike comes down to three things: how fast you spin the pedals, which gear you are in, and how big your wheels are. This calculator ties them together so you can see exactly how quick a given cadence is in a given gear. Cadence is the number of times the pedals go round each minute, measured in revolutions per minute (rpm), and most riders sit somewhere between 80 and 100 rpm on the flat. The gear ratio is the number of teeth on the front chainring divided by the number of teeth on the rear sprocket, and it tells you how many wheel turns you get for each turn of the pedals. Multiply that ratio by the rolling circumference of your wheel and you get the distance you cover with every pedal stroke, known as the development or rollout. Put cadence, gearing and wheel size together and you have your speed. Enter your cadence, your chainring and sprocket tooth counts, and your wheel circumference in millimetres, and the calculator returns your speed in kilometres per hour and miles per hour, along with the gear ratio and the metres you travel per pedal revolution. It is handy for choosing gears, understanding why a higher cadence in an easier gear can match a grind in a harder one, and working out what you will need to spin to hold a target pace.

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At 90 rpm in a 50/15 gear on a 2111 mm wheel you would be travelling 38.0 km/h (23.61 mph).

Wheel circumference is the rolling distance of one full wheel turn: about 2111 mm for a 700x25c road wheel. This is a flat-ground estimate that ignores wind, drivetrain losses and tyre slip.