Bike Gear Ratio Calculator
Work out your gear ratio, gear inches, and development from your chainring, cog and wheel size.
How to use the gear ratio calculator
- Enter your chainring and cog (sprocket) teeth.
- Pick your wheel and tire size.
- Click Calculate to see ratio, gear inches and development.
Ratio, gear inches and development
Gear ratio is simply chainring teeth divided by cog teeth. Gear inches and development translate that into real-world distance per pedal revolution, which is what actually determines how the gear feels.
Frequently asked questions
What is a good gear ratio for cycling?
It depends on terrain. A 2.5–3.5 ratio suits flat riding, while lower ratios (under 2) help on steep climbs. Gear inches let you compare across wheel sizes.
What are gear inches?
Gear inches express how far the bike travels per pedal stroke relative to wheel size — a legacy measure that lets you compare gearing fairly across different wheels.
Related tools
Bike Gear Speed Calculator
See how fast a gear and cadence combination will move you, in km/h and mph.
Wheel Circumference Calculator
Get the circumference value to enter into your bike computer, by tire size or measured diameter.
Power-to-Weight Calculator
Calculate your watts per kilogram (W/kg) — the number that best predicts climbing and racing performance.