🚴 Cycling Speed From Cadence Calculator

Calculate your cycling speed based on your gear setup (in gear inches) and pedaling cadence.

Gear inches

Cadence (RPM)

From pedal revolutions to road speed

Gear inches is the diameter of an imaginary wheel your pedals turn directly, so one pedal revolution rolls out its circumference:

inches per pedal turn = gear inches × π
inches per hour       = inches per turn × cadence × 60
mph                   = inches per hour / 63360      (12 × 5280)
km/h                  = mph × 1.60934

At 54 gear inches and 90 rpm: 54 × π = 169.6 in per turn, times 5,400 turns an hour is 916,088 in, which is 14.5 mph (23.3 km/h). Both inputs scale the answer directly - hold the gear and lift cadence from 90 to 100 rpm and speed rises to 16.1 mph.

Getting the inputs, and what the answer leaves out

Gear inches = wheel diameter in inches × chainring teeth / cog teeth. A 700×25c wheel measures about 26.4 in, so 50/32 gives 41 gear inches and 50/11 gives 120.
Cadence is pedal revolutions per minute. Most riders sit between 80 and 100 rpm; track sprinters pass 130 briefly.
Spin-out is easy to check here. That same 120 in top gear at 100 rpm is 35.7 mph, so if you regularly exceed that you have run out of gear, not legs.

This is the speed the drivetrain produces if you keep pedalling at that cadence. It says nothing about whether you can push the gear - wind, gradient and rolling resistance decide that, and a real ride average is far lower because it includes coasting and stops.

Frequently asked questions

How fast is 90 rpm in a 54 inch gear?

14.5 mph, or 23.3 km/h. Each pedal turn covers 169.6 in, and 90 turns a minute is 5,400 an hour.

What cadence should I ride at?

Most riders settle between 80 and 100 rpm, and pick a gear that keeps them there rather than holding a gear and letting cadence drift. Grinding below about 60 rpm loads the knees for no speed gain.

How do I work out my gear inches?

Multiply your wheel diameter in inches, tyre included, by the chainring teeth divided by the cog teeth. A 26.4 in wheel with a 34t ring and a 28t cog is 32 gear inches.