ConverterHub

Cadence to Speed Calculator

Enter cadence, gear ratio and wheel circumference to get your speed in km/h and mph.

Result

33.42 km/h
20.77 mph

How it is calculated

Each pedal turn spins the rear wheel gear ratio times, and each wheel turn rolls forward one wheel circumference. Speed is km/h = cadence × gear ratio × circumference × 60 ÷ 1000, with cadence in pedal revolutions per minute, the gear ratio as chainring teeth ÷ cog teeth, and the circumference in metres. The 60 turns minutes into hours and the 1000 turns metres into kilometres. Miles per hour is km/h × 0.621371. If the circumference is left empty, the tool uses 2.105 m. Cadence cannot be negative; gear ratio and circumference must be above zero. The result assumes no drivetrain losses, no coasting and no tyre slip.

Worked example

A rider pedals at 90 rpm with a 50-tooth chainring and a 17-tooth cog, a ratio of 50 ÷ 17 ≈ 2.94. The wheel circumference is 2.105 m. Metres per minute: 90 × 2.94 × 2.105 = 557.0. Per hour: 557.0 × 60 = 33,419 m, which is 33.42 km/h. In miles per hour: 33.42 × 0.621371 = 20.77 mph. In a gear one cog larger, the same cadence would give a lower speed.

Try this example →

Common mistakes

  • Typing the wheel diameter or the tyre size in millimetres. The circumference field is in metres, for example 2.105, not 2105.
  • Entering the gear as two numbers, such as 50/17. Divide first and enter about 2.94.
  • Inverting the ratio (cog ÷ chainring), which gives a value below 1 and a very low speed.
  • Using a wheel circumference from a different tyre size. A wider tyre rolls farther per turn, so the speed changes.
  • Expecting the figure to match a bike computer during a climb or in a headwind. It is a theoretical speed from cadence, not measured by GPS.

About this calculator

A cyclist's road speed comes from three factors multiplied together: pedalling cadence (rpm), the gear ratio (chainring teeth ÷ cassette cog teeth), and the wheel circumference. Each pedal revolution turns the rear wheel by the gear ratio, and each wheel revolution covers one circumference of ground.

This calculator chains those together — cadence × gear ratio × wheel circumference, adjusted for units and time — to output speed in both km/h and mph. Cyclists and coaches use it to plan gear selection for a target speed, or to understand why a given cadence feels faster in a taller gear.

Was this helpful?

You can pick up to 3 reactions.

Comments (0)

  • Be the first to comment.

Popular calculators

Loan Calculator

Monthly payment, total interest and full amortization schedule.

Percentage Calculator

Percent change, percent of, and ratio calculations.

Discount Calculator

Calculate final price, savings, and discount amount.

BMI Calculator

Body mass index from height and weight (metric or imperial).

Age Calculator

Compute your exact age in years, months and days from a birth date.

Compound Interest Calculator

Calculate the final amount and interest earned with compounding.

All Calculators