Convert STL to glTF
Convert STL to glTF in your browser. The conversion runs on this page and the file never leaves your computer.
Result
Before you convert: what this keeps and what it destroys
Preserved
- The geometry, triangle for triangle
- Overall dimensions and proportions
- Watertightness, where the input is watertight
Destroyed
- A recorded unit: glTF stores none
↺ the reverse: glTF → STL · about .stl · about .gltf · just view it instead
Why people convert STL to glTF
Getting a print mesh onto a web page, in the readable container.
The practical gain over STL is that the result actually loads in a browser viewer, since nothing on the web reads STL natively while glTF is the format everything on the web reads.
The file written here keeps its buffer embedded as base64, so it is one self-contained file rather than the JSON-plus-.bin pairing that causes so many broken glTF handoffs. Coordinates are divided by 1000, from the millimetres an STL is assumed to be into glTF's metres, which is what stops the model appearing a kilometre wide in a viewer. Take the GLB instead if you care more about size than about being able to read the file.
What you get
You get a plain-text glTF file you can open in an editor containing the same triangles the STL file described. No geometry is added, removed or approximated: mesh-to-mesh conversion is a change of container, and this site's tests check that the triangle count comes out identical.
The output uses metres, as required by the glTF specification.
The conversion runs in your browser. Your file stays on your computer and is not uploaded.
What to check afterwards
- STL carries no unit. The numbers in the file are just numbers, so the conversion assumes millimetres. Check the overall dimensions of the result before you commit to machining or printing it. A file exported from a package set to inches will be 25.4 times out.
- The numbers change. glTF is read in metres and STL in millimetres, so every coordinate is rescaled. The result is the same physical size, but the numbers in the file are different numbers.
If you need something this conversion cannot give you
This pair loses very little. glTF carries what STL carries, so the main reason to choose a different target is what the receiving software accepts.
Going the other way
Convert glTF back to STL. The reverse conversion also works with mesh geometry. It does not reconstruct exact CAD surfaces. Material data and part structure lost in either direction cannot be restored by converting back. Keep the original file for later edits.
How we know this conversion works
This pair was checked against 9 files from the test corpus on 2026-09-04. Each run parses its own output back in and compares the bounding box, the triangle count and, for closed solids, the volume against the input.
A pair that fails those checks doesn't get a page. That's why this site lists 120 conversions and not the several hundred a format-times-format grid would suggest.