engineering

Gear Ratio Calculator

Calculate gear ratios, output RPM, and torque for single or multi-stage gear trains

Gear Ratio Calculator

Calculate gear ratios, output RPM and torque for single or multi-stage gear trains.

rpm
N·m
Driver Teeth N₁Driven Teeth N₂

Stage 1 driver

Stage 1 driven

Gear Ratio GR

3.0000 : 1

Output RPM

600.00 rpm

Output Torque

150.000 N·m

Speed reducer

×0.333 speed

Formulas

GR = N₂/N₁ (per stage, multiply for multi-stage)
ω_out = ω_in / GR = 600.00 rpm
T_out = T_in × GR = 150.000 N·m (no loss)

How to Use This Calculator

1

Enter your input values

Fill in all required input fields for the Gear Ratio Calculator. Most fields include unit selectors so you can work in your preferred unit system.

2

Review your inputs

Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors.

3

Read the results

The Gear Ratio Calculator instantly computes the output and displays results with units. All calculations happen in your browser — no loading time and no data sent to a server.

Formula Reference

Gear Ratio

GR = N_input / N_output = ω_input / ω_output

Variables: N = number of teeth, ω = angular velocity (RPM)

Output Torque

T_out = T_in × GR × η

Variables: η = gear train efficiency

When to Use This Calculator

  • •Use the Gear Ratio Calculator when solving homework or exam problems that require quick numerical verification of your hand calculations.
  • •Use it during the design phase to rapidly iterate on parameters before running detailed finite element simulations.
  • •Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility.
  • •Use it to generate reference data for a technical report or presentation without manual computation.

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