Gear Ratio Calculator

Gear ratio from the tooth count of the drive and driven gears, with the resulting speed reduction.

Formula

Gear ratio = Driven gear teeth / Drive gear teeth

Assumptions

Gear ratio from the tooth count of the drive and driven gears, with the resulting speed reduction.

How to read it

A ratio above 1 reduces rotational speed and multiplies torque; below 1 (overdrive), the opposite. A final drive reads the same way: ring gear teeth divided by pinion teeth.

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