Convert STL to GLB
Convert an STL into a GLB for use on the web, in three.js, or in a game engine.
Free, no account, up to 50 MB per file. Uploads are private and deleted after 24 hours unless you sign in, which claims them and keeps them for 7 days.
What survives STL → GLB
- Geometry
What is not carried across
- Nothing the STL contained — an STL is triangles only, so the GLB carries everything it had.
About STL files
- STL stores triangles and nothing else — no materials, no textures, no UVs, no colours, and no object names.
- STL has no unit declaration. The numbers are carried across unchanged, so a model authored in millimetres stays in millimetres.
- Normals are recomputed from the triangles rather than trusted from the file, which is what removes the faceting some exporters bake in.
Why GLB
- One file carrying geometry, materials and textures — nothing to lose in transit.
- The native format for glTF viewers, three.js, Babylon.js, Unity and Unreal import, and the web generally.
- Compact binary layout, so it downloads and parses faster than an equivalent text format.
Common problems
- The model renders grey.
- That is the STL faithfully converted: it had no material data. Assign one in your engine, or start from a textured source.
- The model is enormous or invisible in the viewer.
- STL declares no units. Scale it in your engine after import.
After converting
Converting changes the container, not the geometry — a heavy model stays heavy. If the result is destined for the web or a game engine, reducing its triangle count is the part that makes it load faster.