Gear Ratio Calculator
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Ratio compares chainring teeth to rear cog teeth. Higher ratio means harder gear.
gear ratio = chainring teeth / cog teethGear inches express equivalent diameter of a direct-drive wheel. Useful for comparing bikes with different wheel sizes.
gear inches = gear ratio × wheel diameter (in)Meters or inches of travel per crank revolution accounts for tire circumference directly.
development (m) = gear ratio × wheel circumference (m)Updated: July 2026
Compare 11-34 vs. 11-36 cassettes with a 46T chainring for climbing gears.
Find a 48×17 or similar ratio that matches your flat-city cadence target.
Check lowest gear inches for steep trail climbs with a 32T chainring.
A larger cog lowers gearing only if the chainring stays the same.
Actual tire height changes development. Measure or use labeled ETRTO when precision matters.
Compare every chainring and cog combo on your bike. Enter tooth counts and wheel size to get gear ratio, gear inches, and meters of development.