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Sports and fitness

Bike Cadence Calculator

Updated · Standard formula, shown below

Cadence 71 rpm
Gear ratio
3.333
Result
Distance per pedal turn
7.02 m
Result
Speed
30 km/h
You entered

This calculator works out your pedalling cadence from speed and gearing. Enter your speed, the teeth on the front chainring and the rear cog, and the wheel circumference, and you get the gear ratio, the distance per pedal turn and the cadence in rpm.

Formula

Gear ratio = chainring ÷ cog. Development (metres per crank turn) = ratio × wheel circumference. Cadence = speed in metres per minute ÷ development = (v × 1000 ÷ 60) ÷ development.

  • v: speed in km/h (mph × 1.609344)
  • cr, cog: tooth counts
  • wc: rolling circumference of the wheel in mm (a 700×25c road tyre is about 2105 mm)

Worked Example

Riding at 30 km/h in a 50 × 15 gear on a 2105 mm wheel.

  1. Ratio = 50 ÷ 15 = 3.333
  2. Development = 3.3333 × 2.105 m = 7.02 m per pedal turn
  3. 30 km/h = 30,000 ÷ 60 = 500 m per minute
  4. Cadence = 500 ÷ 7.0167 = 71 rpm

Limits and common mistakes

  • Measure the wheel by rolling it one full turn under load; tyre width and pressure change it.
  • The result assumes no coasting: if you freewheel part of the time, your real cadence while pedalling is higher.
  • Keep the wheel in millimetres; entering 2.105 (metres) gives a cadence 1000 times too high.
Formula used
in v | Speed | km/h | 30 | 0
in cr | Chainring teeth | teeth | 50 | 0
in cog | Rear cog teeth | teeth | 15 | 0
in wc | Wheel circumference | mm | 2105 | 0
out rpm | Cadence | rpm | (v * 1000 / 60) / (cr / cog * wc / 1000) | 0
out r | Gear ratio | - | cr / cog | 3
out dev | Distance per pedal turn | m | r * wc / 1000 | 2

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.