Convert 3D files between STL, OBJ, 3MF, PLY and GLB. Convert one file or a whole folder at once, and resize on the way. Everything runs in your browser, so your files are never uploaded.
How to convert OBJ to STL
- Add your OBJDrop an OBJ file from Blender, ZBrush, Maya, a 3D scan or a model site. You can add several at once.
- Check the sizeEach file shows its size in millimeters. If it looks tiny or huge, change the scale before converting.
- Download your STLClick Convert to get an STL that opens in any slicer, or a ZIP when you convert several files.
Why convert OBJ to STL?
Most slicers open OBJ, but STL is the standard for 3D printing. Marketplaces, print services and older slicers often accept STL only.
When you are not sure what software someone else uses, STL is the safest file to send.
Textures and materials
OBJ files often come with an MTL file and texture images. A printer only needs the shape, so the STL keeps the geometry and leaves textures out.
Faces with four or more corners are split into triangles automatically.
Units and size
OBJ files don't store units. Slicers read the numbers as millimeters, so a model made in meters can open 1000 times too small.
If that happens, set the scale to 100000% to turn meters into millimeters.
Frequently asked questions
Are textures kept when I convert OBJ to STL?
No. STL only stores the shape of a model, so textures, colors and the MTL file are not used. The geometry is converted exactly.
Why is my STL tiny in the slicer?
The OBJ was probably made in meters, for example in Blender. Slicers read STL in millimeters, so set the scale to 100000% and convert again.
Can it convert OBJ files with quads?
Yes. Faces with four or more corners are split into triangles, which is what STL needs.
Can I convert several OBJ files at once?
Yes. Add as many as you like, and they come back together in one ZIP.
Is my file uploaded?
No. Your files are converted by your browser on your own device and never sent to our server. That also makes it fast, even for large files.