Gear ratio
A 32-tooth chainring driving a 16-tooth sprocket is 2.00:1: the rear wheel turns twice for each crank revolution, ignoring hub internals.
Velopedia Tools
Gear Ratio
Bicycle Gear Ratio Calculator
Compare the usable gearing of a bicycle from chainring, cassette and wheel dimensions. Calculate ratios, gear inches, development, speed at cadence, overall range and the percentage jump between adjacent cassette sprockets.
Complete gear table
Each row shows the calculated output for one chainring/cassette combination at the selected cadence.
| Chainring | Cog | Ratio | Gear inches | Development | Speed |
|---|
Cassette spacing
Percentage jumps describe how large each shift step is. Smaller jumps preserve cadence more closely; larger jumps provide faster changes in mechanical advantage.
How the calculations work
Ratio = front chainring teeth ÷ rear sprocket teethDevelopment = wheel circumference × ratio · Speed = development × cadence × 60
Gear ratio is independent of wheel size, while gear inches, development and road speed are not. When measured rollout is supplied, Velopedia uses it directly. Otherwise, circumference is estimated from bead-seat diameter plus twice the entered mounted tire width. Real tire height varies with casing, rim width and inflation, so measuring one loaded or unloaded wheel revolution gives a better speed/development result.
What the metrics tell you
Gear inches
A traditional wheel-size-normalized measure useful for comparing bicycles with different wheel diameters. Lower values mean easier gearing.
Development
The linear distance the bicycle travels for one full crank revolution. It is convenient for comparing actual rollout across wheel sizes.
Overall range
Highest ratio divided by lowest ratio, expressed as a percentage. Range describes the spread between the extremes, not the size of the steps between them.
Model scope
This calculator models conventional chain-driven derailleur drivetrains with one or more front chainrings. Internal-gear hubs, gearboxes and other systems with internal reduction ratios require those internal ratios to be included separately. Speed values are theoretical and do not account for tire deformation, drivetrain losses, coasting or aerodynamic effects.