How to convert STL to OBJ
- Drop your .stl file into the box above, or click Choose file.
- Check the 3D preview, size and triangle count.
- Make sure OBJ is selected as the output format. Adjust scale or up-axis if needed.
- Click Download. The .obj file is created instantly on your device.
Why convert STL to OBJ?
OBJ is the easiest way to bring a printable model into Blender, Maya or a game engine for texturing, sculpting or rendering. The geometry is copied one-to-one; OBJ simply has no use for STL's per-triangle normals, so smooth normals are recalculated by the receiving program.
What changes in the conversion
- Units. STL is in metres; OBJ is usually read as millimetres. Small models are scaled ×1000 automatically – you can change this before downloading.
- Geometry is preserved. Every triangle, with all object transforms applied, ends up in the new file.
STL vs OBJ
| STL | OBJ | |
|---|---|---|
| Full name | Stereolithography | Wavefront OBJ |
| Stores | geometry only | geometry, normals and UV coordinates (materials live in a separate .mtl file) |
| Colour | No | No |
| Textures | No | Yes |
| Units | none – most programs read STL numbers as millimetres | none |
| Exact CAD geometry | No | No |
About the formats
STL (Stereolithography) was created by 3D Systems in 1987 for its stereolithography printers. It describes only the surface of a model as a list of triangles, without colour, materials or units. It is the default file for 3D printing and the format almost every slicer (Cura, PrusaSlicer, Bambu Studio, Chitubox) opens.
OBJ (Wavefront OBJ) was introduced by Wavefront Technologies for its Advanced Visualizer software. It is a plain-text mesh format that stores vertices, faces, normals and texture coordinates, with materials in a separate MTL file. It is widely used to move models between 3D modelling programs such as Blender, Maya, 3ds Max and ZBrush.
Frequently asked questions
Is this converter free?
Yes. You can convert STL to OBJ for free – up to 3 conversions a day, with no sign-up and no watermark. If you need more, Pro gives you unlimited conversions and batch conversion (free for 7 days).
Are my files uploaded to a server?
No. The conversion runs entirely in your browser using WebAssembly and JavaScript. Your model never leaves your computer, which also makes it safe for confidential parts and patient data.
Is there a file size limit?
There is no fixed limit. Files of a few hundred megabytes work on a typical laptop; the practical limit is your device's memory.