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OBJ to STL converter

Drop your .obj file — we convert it to .stl right in your browser. Files never leave your computer.

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Drop your OBJ file here
Accepts .obj · converts to .stl

OBJ vs STL— what's the difference?

OBJ.obj

Human-readable Wavefront mesh format — ubiquitous in 3D graphics, game art, and asset pipelines. Pairs with a .mtl material file.

Strengths
  • Supported by virtually every 3D tool (Blender, Maya, 3ds Max, Unity, Unreal…)
  • Plain-text, easy to diff and hand-edit
  • Keeps UV coordinates and vertex normals, unlike STL
  • Material references via companion .mtl file
Limitations
  • Text format — larger on disk than binary meshes
  • No scene hierarchy, no animation, no skeletons
  • Materials live in a separate file; easy to lose
Typical use: 3D art pipelines, DCC handoff, asset archives
STL.stl

Triangle-mesh format that every 3D printer slicer understands. Geometry only — no units, colours, or assemblies.

Strengths
  • Universal 3D printing format — Cura, PrusaSlicer, Bambu Studio all speak STL
  • Tiny, simple, extremely fast to load
  • Great for meshing workflows, simulation pre-processors, quick previews
Limitations
  • Triangulated approximation — curved surfaces lose precision
  • No colour, material, or assembly data
  • One shell per file by convention (multi-body gets flattened)
Typical use: 3D printing, rapid prototyping, mesh-based workflows

How to convert OBJ to STL

  1. 1
    Drop a .obj file onto the page (or click to browse). Runs entirely in your browser — no upload.
  2. 2
    Preview the mesh in 3D and confirm it looks right. Watch the triangle count in the sidebar.
  3. 3
    Click Download .STL to save a binary STL. Open it in Cura, PrusaSlicer, or Bambu Studio to print.

FAQ

Is my OBJ uploaded anywhere?

No. Conversion runs in your browser using Three.js' OBJ loader and STL exporter. Nothing is sent to a server.

Does this strip the material / texture information?

Yes — STL is geometry-only, so any .mtl material, UV, or texture data in the source OBJ is dropped. If you need colour, export to 3MF or GLB instead (coming soon on this site).

Can I print the resulting STL straight away?

If the OBJ mesh is manifold (watertight, no flipped normals), yes. If your slicer complains, load the STL in Blender → Mesh → Clean Up → Merge by Distance, then re-export.

Is the output binary or ASCII STL?

Binary — about 5× smaller than ASCII and loads faster in every slicer.

What about quad meshes from Blender?

Three.js triangulates quads and n-gons automatically on import. The output is always pure triangles, as required by STL.

Related converters

STL → OBJSTEP → STLSTEP → OBJFBX → GLB