OBJ to STL Converter
Convert a Wavefront OBJ to binary STL for 3D printing. Materials and textures are dropped — the shape is kept. Runs in your browser.
Drag & drop your OBJ file here
or click to browse
Supported Formats
Format Information
Source Format
OBJ.obj
OBJ (Wavefront)
The Wavefront OBJ format is a plain-text mesh description that has been the default interchange format for computer graphics since the 1990s. Geometry lives in the .obj file; colour and texture references live in a companion .mtl file.
What it carries: Vertex positions, normals, texture coordinates and polygon faces, plus what MTL can express: a diffuse colour, opacity, shininess and a single diffuse texture map. There are no PBR metal/roughness values, no normal maps, no vertex colours and no animation.
Open a OBJ file in the viewerTarget Format
STL.stl
STL (Stereolithography)
STL is an additive-manufacturing format from the 1990s: a flat list of triangles and nothing else. It has no concept of a scene, a material or a texture, which is why it is the lingua franca of 3D printing and also its most lossy interchange format.
What it carries: Triangle positions and, optionally, one facet normal per triangle. No UVs, no vertex colours, no materials, no node hierarchy, no animation.
Open a STL file in the viewerAbout this conversion
A print-ready shape file. The OBJ's positions and faces are triangulated into a binary STL with computed normals, and the material layer is left behind because STL has nowhere to put it.
Why convert OBJ to STL
- Send a modelled OBJ straight to a slicer for FDM or resin printing.
- Hand the shape to a mesh-repair or decimation tool that only reads STL.
- Produce a compact, dependency-free geometry file for a colleague without 3D software.
What happens during the conversion
Geometry
Positions and faces are triangulated and written as a binary STL with one facet normal per triangle. OBJ group structure is dropped and the meshes are merged into one coordinate space.
Materials and textures
None. STL cannot store an .mtl, so the diffuse colour and diffuse map you may have prepared are discarded along with the UVs.
Common use cases
- Preparing a printable model from an OBJ asset.
- Running mesh analysis or repair in an STL-only tool.
- Sharing a shape-only version of a textured model.
Limitations of this conversion
- Materials, textures, UVs and vertex colours are all lost — this is inherent to STL, not a conversion error.
- Grouping and object structure are flattened into one triangle list.
- There is no unit metadata, so confirm the scale in your slicer before printing.
How to convert OBJ to STL
Three steps in the browser. Nothing is uploaded to a server, so an unwieldy file is limited only by your own device's memory.
Upload your .obj
A ZIP including the .mtl and textures is fine, though the material will not survive the conversion.
Convert to STL
Geometry is triangulated and written as a binary STL with computed normals.
Check the scale in your slicer
STL has no unit field, so confirm the model is the size you expect.
Related tools and formats
Other conversions from this format
Check the file in a viewer
Frequently Asked Questions
Questions people ask when turning OBJ files into STL.
Looking for a different direction? See every supported conversion.