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STL to OBJ converter

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

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

STL vs OBJ— what's the difference?

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
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

How to convert STL to OBJ

  1. 1
    Drop a .stl file onto the page (or click to browse). Everything runs locally — nothing is uploaded.
  2. 2
    Preview the mesh in 3D. Orbit to check the geometry, confirm the triangle count looks right.
  3. 3
    Click Download .OBJ to save a Wavefront file. Import it straight into Blender, Maya, Unity or Unreal.

FAQ

Is my STL file uploaded to a server?

No. Everything happens in your browser — Three.js loads the STL, re-exports to OBJ, and hands you a download link. Nothing leaves the machine.

Will I get a .mtl material file?

No — STL has no material data to carry over, so we only emit the .obj geometry file. Assign materials inside your target tool (Blender, Unity, etc).

Does converting STL to OBJ add UV coordinates?

No. UVs don't exist in STL and can't be invented reliably. If you need UVs, unwrap the mesh after import in Blender (Smart UV Project gives decent results for prints).

Why is my OBJ larger than the STL?

OBJ is a text format; STL (binary) is compact. Expect ~2–3× the size. The trade-off is human readability and wider DCC support.

What's the vertex / triangle limit?

There is no hard cap — your browser's RAM is the ceiling. Meshes up to a few million triangles convert fine on modern desktops.

Related converters

OBJ → STLSTEP → STLSTEP → OBJFBX → GLB