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Scale STL

Resize a model to an exact width, height or depth in millimetres, by percentage, or fix inch/metre files – and download the scaled file.

Exact size in mmInch ↔ mm presetsLock proportionsNo upload
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How to scale an STL

  1. Drop the file into the box above; its current size is shown.
  2. Type a percentage, or type the size you need on any axis – the others follow when Keep proportions is ticked.
  3. Use a preset for unit problems: inches → mm (×25.4), metres → mm (×1000).
  4. Download as STL, 3MF, OBJ or STEP.

Why is my model tiny or huge?

STL has no units. A model designed in inches looks 25.4× too small in a millimetre slicer; a GLB-exported model in metres looks 1000× too small. Details in STL units and scale explained.

Frequently asked questions

Can I stretch only one axis?

Yes – untick Keep proportions and type the new size for that axis.

Is it free?

Yes – up to 3 downloads a day are free, with no sign-up or watermark. Pro (free for 7 days) makes it unlimited.

Is my file uploaded?

No. The file is processed in your browser and never leaves your device.