Convert STL to OBJ
Convert an STL into a Wavefront OBJ that any 3D application can open.
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 → OBJ
- Geometry
What is not carried across
- Nothing the STL contained — an STL is triangles only, so the OBJ 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 OBJ
- Read by essentially every DCC application ever written; a safe interchange format.
- Plain text, so it can be inspected and diffed.
Common problems
- The OBJ has no materials.
- An STL never had any. Materials have to be authored after conversion; nothing can reconstruct them.
- The model looks faceted.
- STL stores flat triangles. Apply smooth shading in your application, or use a source that carries normals.
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.