Gear Train Ratios

A small gear driving a big one trades speed for torque. Watch two gears mesh and see the ratio, output rpm, and output torque update live.

Gear Train RatiosLive

trade speed for torque

Controls

Presets

Driver teeth

Driven teeth

Input speed (rpm)

Input torque (N·m)

A larger driven gear turns slower but with proportionally more torque — the ratio equals the tooth-count ratio. Gears trade speed for force, exactly like a lever.

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Data Inspector

Gear ratio3.00 : 1

Output speed20.0 rpm

Output torque6.0 N·m

Governing equation

\frac{ω _{o u t}}{ω _{in}} = - \frac{N _{in}}{N _{o u t}} = - \frac{12}{36}, τ_{o u t} = τ_{in} \cdot \frac{N _{o u t}}{N _{in}} = 6.0 N\cdotm

Reading this result: Reduction drive: the driven gear turns 3.0× slower but multiplies torque 3.0× — trading speed for pulling force, like low gear on a bike.

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How it works

For meshing gears the ratio equals the driven-to-driver tooth-count ratio. Output speed divides by the ratio while output torque multiplies by it (ignoring friction), because power is conserved. This is the basis of every gearbox, from bicycles to wind turbines. Educational tool.

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Frequently asked questions

Is this gear ratio calculator tool really free?▾

Yes. Gear Train Ratios runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.

Do I need to install anything?▾

No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.

Can I save or share my simulation?▾

Create a free account to save projects, and use a shareable embed or minted DOI to publish a live, interactive version anywhere.

How accurate are the results?▾

The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.