basic

Gear Ratio Calculator

Output speed and torque from gear-tooth counts.

Compute the gear ratio, output rotational speed, and output torque of a single-stage spur-gear pair from the number of teeth on each gear and the input speed and torque.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

rpm
N·m

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Ratio = N_driven / N_driver. Output rpm = input_rpm / ratio. Output torque = input_torque · ratio.

In depth

Compute the gear ratio, output rotational speed, and output torque of a single-stage spur-gear pair from the number of teeth on each gear and the input speed and torque.