Free GLB to STL Converter
GLB to STL Converter turns GLB, glTF, OBJ, FBX, STL, 3MF, PLY, STEP and IGES models into STL, 3MF, OBJ, GLB or PLY files. Set the source units so the size is right in millimetres, rotate Y-up to Z-up, merge meshes and optionally repair holes and flipped normals, checked with Manifold. Several files convert at once into a ZIP.
- Output:
- STL, 3MF, OBJ, GLB or PLY
- Source units:
- mm, cm, m, in or ft
- Repair:
- Welding, normals, holes, Manifold
- Price:
- Free
- Runs:
- Locally, in your browser
- Uploads:
- None: files never leave your device
- Account:
- Not needed
Quick answers
Are my models uploaded?
No. Files are read, converted and repaired by your browser; nothing is sent to a server.
Why is my converted STL tiny or huge in the slicer?
STL, OBJ and PLY store plain numbers without units. glTF uses metres and FBX often centimetres, while slicers assume millimetres. Set the units of the source file and the converter scales the model to the right size.
Processed on your device: your files are never uploaded. How it works
Network activity in this tab
What this page has requested since you opened the site in this tab. An upload is any request that sends data: POST, PUT, PATCH or a request with a body.
No uploads: nothing has been sent from this page.
No network requests yet.
To see every request, open your browser's developer tools (Network tab).
How to use the GLB to STL Converter
- Drop one or more 3D files (GLB, glTF with its .bin and textures, OBJ with MTL, FBX, STL, 3MF, PLY, STEP or IGES).
- Pick the output format and check the source units: the preview shows the real size in millimetres and inches.
- Choose the up axis, bed placement and whether to merge meshes; turn on repair if the model is not watertight.
- Download the converted file, or convert every file at once into a ZIP.
Credits & open source
Our own code plus open-source libraries. Thank you to the people who make these projects.
- three.js3D rendering engine and model loaders (glTF, STL, OBJ, FBX, 3MF, PLY). © three.js authors (Ricardo Cabello and contributors) · MIT
- Draco decoderDecoder for Draco-compressed glTF meshes (shipped with three.js). © Google LLC · Apache-2.0
- occt-import-jsSTEP/IGES/BREP importer (OpenCascade compiled to WebAssembly), loaded unmodified as a separate file. © Viktor Kovacs; Open CASCADE Technology by Open Cascade SAS · LGPL-2.1
- ManifoldRobust mesh boolean and repair library compiled to WebAssembly. © Emmett Lalish and Manifold contributors · Apache-2.0
- fflateFast ZIP compression for batch downloads. © Arjun Barrett · MIT
Web platform APIs used: WebGL, Web Workers, WebAssembly, File API, Pointer Events, URL API, localStorage.
Full license texts: third-party notices · all credits
Frequently asked questions
Can I convert STL to 3MF or 3MF to STL?
Yes. 3MF keeps the unit, the separate objects and their colors; STL keeps only triangles. Both are written in millimetres by default.
What does the repair do?
It joins duplicate vertices, removes broken triangles, makes all normals point outwards, closes holes and then checks the result with the Manifold geometry library, which reports whether it is a valid closed solid and its volume.
Can I convert STEP files to STL or OBJ?
Yes. STEP and IGES are tessellated in your browser with OpenCascade (about 8 MB downloaded the first time) and can then be saved in any of the mesh formats.
Are textures kept?
Only in GLB output when meshes are not merged or repaired. STL has no colors; 3MF, OBJ and PLY keep one color per object.