Calculate bike gear ratio, gear inches, rollout, development, speed at cadence, climbing gear, top speed, and drivetrain range. This calculator works for road bikes, mountain bikes, gravel bikes, touring bikes, BMX, single-speed bikes, e-bikes, and bikepacking setups.
Gear ratio:
The calculator divides chainring teeth by rear cog teeth. A lower ratio is easier to pedal, while a higher ratio is faster but harder to turn.
Gear inches:
Gear inches combine gear ratio and wheel diameter so you can compare bikes with different wheel sizes.
Speed and cadence:
The calculator estimates rollout, development, and speed at your selected cadence so you can compare climbing gears and top-speed gears.
A bike gear calculator helps choose chainrings, cassettes, single-speed setups, climbing gears, gravel gearing, mountain bike gearing, touring gearing, and bikepacking drivetrain setups.
Real-world pedaling difficulty also depends on tire size, rider strength, bike weight, cargo weight, grade, wind, terrain, tire pressure, rolling resistance, and cadence preference.
This calculator uses common bicycle gearing formulas:
Gear Ratio = Chainring Teeth ÷ Rear Cog Teeth
A bike gear ratio is the number of chainring teeth divided by the number of rear cog teeth. For example, a 32 tooth chainring with a 16 tooth cog is a 2.0 ratio.
An easier climbing gear uses a smaller chainring, a larger rear cog, or both. A ratio near or below 1:1 is helpful for steep climbs and loaded riding.
Gear inches estimate how far a bike travels per pedal revolution compared with wheel size. Lower gear inches feel easier; higher gear inches feel faster but harder.
Use a larger chainring, smaller rear cog, larger wheel diameter, or higher cadence. Make sure the gearing still works for your climbs and terrain.