Scale and resize 3D models online

Resize STL, OBJ, GLB, 3MF, and STEP files by a factor, to an exact dimension, or between inches and millimeters. Free, right in your browser.

Scale the attached model by 2×

Files are processed entirely in your browser. Nothing is uploaded to a server.

Any 3D edit is just a prompt away.
Try the full chat free

How to resize a 3D model

Attach your model and choose a mode: multiply by a factor, hit an exact dimension on one axis (the other axes scale proportionally), or convert between inches and millimeters. Then press "Scale it" and download the resized STL.

The inches to mm preset fixes the classic "my STL imports 25.4× too small" problem caused by CAD tools that export in imperial units.

Frequently asked questions

Can I scale each axis by a different amount?

This tool scales uniformly to preserve the model's proportions, which is what you want for printed parts. For non-uniform stretching, describe the change in GrandpaCAD chat ("stretch this bracket to 120 mm long but keep the holes 5 mm") and get a proper parametric edit instead of a distorted mesh.

Why is my slicer showing a different size?

Check the slicer's import unit setting. STL has no units, so a file saved here as 100 mm will read as 100 of whatever unit the slicer assumes, which is almost always millimeters.

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