Convert OBJ to STL
Convert OBJ to STL free in your browser. No upload, no signup, no watermark. Files stay on your device.
drop a .obj file
or click to browse
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more obj & stl
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how to convert obj to stl
Drop your OBJ file
Drag your OBJ file into the drop zone above, or click the box to pick a file from your computer or phone. The browser reads the file directly — nothing uploads.
Click Convert
The page runs three.js on your device to decode the Wavefront OBJ and encode it as Stereolithography. Most conversions finish in a few seconds; large or codec-heavy files (RAW, video) can take longer.
Download the STL file
When the conversion finishes, the STL file is ready to download. Save it anywhere on your device.
FAQ
common questions
Why convert OBJ to STL?
3D printing — STL is the universal slicer input format. Every slicer (Cura, PrusaSlicer, Bambu Studio, Simplify3D, Lychee, Chitubox) accepts STL without question; OBJ support is widespread but occasionally inconsistent. If you're sending a model to a 3D printer or sharing for printing, STL is the safer format.
Will I lose materials, textures, and colours?
Yes — STL stores geometry only. Any materials, textures, UV maps, or vertex colours in the OBJ are dropped. For 3D printing this is usually fine (printers don't need texture data) but if your OBJ has visual fidelity you care about, the conversion strips it entirely.
Will the geometry survive exactly?
Yes — every face in the OBJ becomes one or more triangles in the STL. Quads and n-gons are automatically triangulated; vertex normals come along; the resulting STL is geometrically equivalent to the source OBJ.
Will the STL be smaller than the OBJ?
Usually yes — STL is binary (compact per triangle); OBJ is text (verbose). A 20 MB OBJ commonly becomes an 8–12 MB STL. The size reduction is from removing the material data and from binary vs text encoding.
Is binary or ASCII STL better?
Binary. ASCII STL is human-readable but ~5× larger than binary for the same geometry. Every modern slicer reads binary; that's the default for STL exports across all 3D modelling tools. The converter produces binary STL.