How to convert STL to glTF
- Drop your .stl file into the box above, or click Choose file.
- Check the 3D preview, size and triangle count.
- Make sure glTF is selected as the output format. Adjust scale or up-axis if needed.
- Click Download. The .gltf file is created instantly on your device.
Why convert STL to glTF?
glTF is the standard 3D format of the web; converting STL to glTF lets you display a printable model in any web viewer.
What changes in the conversion
- Up-axis. STL is usually Z-up while glTF is Y-up; the model is rotated so it stands the right way up. Untick "Convert up-axis" to keep the raw coordinates.
- Geometry is preserved. Every triangle, with all object transforms applied, ends up in the new file.
STL vs glTF
| STL | glTF | |
|---|---|---|
| Full name | Stereolithography | GL Transmission Format |
| Stores | geometry only | geometry, materials, textures, hierarchy and animations |
| Colour | No | Yes |
| Textures | No | Yes |
| Units | none – most programs read STL numbers as millimetres | metres by specification |
| Exact CAD geometry | No | No |
About the formats
STL (Stereolithography) was created by 3D Systems in 1987 for its stereolithography printers. It describes only the surface of a model as a list of triangles, without colour, materials or units. It is the default file for 3D printing and the format almost every slicer (Cura, PrusaSlicer, Bambu Studio, Chitubox) opens.
glTF (GL Transmission Format) was published by the Khronos Group (version 2.0 since 2017). It is a JSON scene description that references binary buffers and textures, either as separate files or embedded. It is the "JPEG of 3D" – the most common format for real-time 3D on the web and in engines like three.js, Babylon.js and Unity.
Frequently asked questions
Is this converter free?
Yes. You can convert STL to glTF for free – up to 3 conversions a day, with no sign-up and no watermark. If you need more, Pro gives you unlimited conversions and batch conversion (free for 7 days).
Are my files uploaded to a server?
No. The conversion runs entirely in your browser using WebAssembly and JavaScript. Your model never leaves your computer, which also makes it safe for confidential parts and patient data.
Is there a file size limit?
There is no fixed limit. Files of a few hundred megabytes work on a typical laptop; the practical limit is your device's memory.