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Gear Ratio Calculator

Calculate gear ratio, gear inches, meters of development and speed at cadence for any chainring, cog and wheel size, for bicycles and dirt bikes.

Vehicle

Gear range

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Easiest gear – · hardest –

CogRatioGear in.km/h

Final drive ratio

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Shorter gearing (higher ratio) gives stronger acceleration and a lower top speed. Always replace chain and sprockets as a set, and check chain length after changes.

How the gear ratio calculator works

What gear ratio, gear inches and speed will I get? For steep climbs on a bicycle, a 1:1 ratio or lower (for example a 32T chainring with a 34T or larger cog) lets most riders keep a comfortable cadence. Modern 1x mountain bikes reach around 0.6:1 with 52T cassettes.

  1. Gear ratio = chainring teeth ÷ cog (or rear sprocket) teeth.
  2. Gear inches = gear ratio × wheel diameter in inches. Development (meters) = gear ratio × wheel circumference.
  3. Speed = cadence (rpm) × development × 60 ÷ 1000 (km/h). For dirt bikes, a higher final-drive ratio (larger rear sprocket) gives more acceleration and lower top speed.

Results are estimates to help you plan and compare. Always follow your manufacturer's specifications, especially for charging, tire pressure and load limits. Found a problem with this tool? Let us know.

Gear ratio questions, answered

What is a good gear ratio for climbing?

For steep climbs on a bicycle, a 1:1 ratio or lower (for example a 32T chainring with a 34T or larger cog) lets most riders keep a comfortable cadence. Modern 1x mountain bikes reach around 0.6:1 with 52T cassettes.

What does going up one tooth on a dirt bike sprocket do?

Adding one tooth to the rear sprocket (or removing one from the front) shortens the gearing. You get stronger acceleration and a lower top speed. One tooth on the front sprocket changes the ratio about as much as three teeth on the rear.

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