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Gear Generator

Generate a printable spur gear and download it as an STL — set the teeth, module, thickness and bore in your browser.

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Set your gear below, then download the STL.

How to use

  1. Set the number of teeth and the module — the module is the size per tooth in millimetres, so a bigger module makes a bigger, chunkier gear.
  2. Set the thickness (how tall the gear is) and the bore diameter (the round hole through the middle for an axle or shaft). Use 0 for no hole.
  3. Watch the live 3D preview update as you type, then press Download STL to save a printable model you can open in any slicer.

FAQ

What is the module, and how does it set the gear size?

The module is the tooth size in millimetres — it is the pitch diameter divided by the number of teeth. Two gears only mesh if they share the same module, so pick one module and use it for every gear in a set. The overall diameter is roughly module × (teeth + 2).

Will these gears actually mesh and turn?

This tool draws a simplified involute approximation, which is great for light-duty printed gears, hand-cranked toys, prototypes and demos. As long as two gears share the same module they will mesh and turn. For high-load or precision drivetrains use dedicated CAD with a true involute profile.

Is anything uploaded, and what file do I get?

Nothing is uploaded — the gear is built and exported entirely in your browser, so it works offline and stays private. You download a binary STL where 1 unit equals 1 millimetre, ready to drop straight into your slicer.