CalculatorsCadence to Speed Calculator

Cadence to Speed Calculator

Speed is cadence times how far one crank revolution takes you. Hold 90 rpm and change the cog if you want a different speed without changing fitness.

Inputs

Cadence (rpm)Chainring teethCog teethWheel

Results

Speed: 21.0 mph
Roll-out: 20.55 ft

How the number is made

Roll-out (m) = (chainring ÷ cog) × wheel circumference. Speed (km/h) = cadence × roll-out × 60 ÷ 1000.

Assumes no wheel slip and the labelled tyre height. A headwind does not change this number; it changes the watts you need.

Related calculators

Gear Inches and Roll-out Calculator
The same gear, expressed as development instead of speed.
Power-to-Weight Calculator
Speed at a cadence still has to be paid for in watts.

Questions

What cadence should I use?

90 rpm is a useful default on the road. Climbs often fall to 70–80. Track sprinters go well above 110.

Why is my GPS slower?

This is ground speed in still air with the tyre you picked. GPS also includes wind, braking and a different tyre circumference.

Does cadence speed include wind or gradient?

No. Speed is cadence times roll-out. It is the speed of the wheel, not the power required to hold that speed.

Related gear

Cadence sensor
The rpm in this formula is the one a sensor records, not the one you feel.
$30–$70

Disclaimer — no professional advice, no liability

These calculators are simplified estimates for education. They are not a bike fit, a structural inspection, or a torque specification that overrides the number printed on a part. Confirm chain length, spoke length, tire fit and bolt torque on the bicycle before you ride.

These calculators, pages and any related content are provided “as is” and “as available”, solely for general educational and informational purposes. They are simplified mathematical estimates, not a professional bike fit, a structural inspection, a manufacturer torque specification or a training, nutrition or medical plan.

Results can be wrong, incomplete or inapplicable to your frame, wheels, tires, drivetrain or suspension. You must independently verify every figure, assume all risk, and confirm chain length before you cut, spoke length before you lace, tire and rim compatibility before you inflate, and the torque printed on the part before you tighten it.

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