STL to OBJ Converter

Convert .stl files into a Wavefront .obj (with an .mtl) for Blender, game engines and 3D tools. Several STLs become several named objects in one OBJ.

How to convert STL to OBJ

Drop one or more .stl files above.
Keep OBJ selected and pick the up axis: Z up for CAD and slicers, Y up for Blender and game engines.
Click Download OBJ — you get a ZIP with the .obj and .mtl.

Why convert to OBJ

OBJ is read by almost every 3D program, including ones that ignore STL.
The mesh is indexed: shared corners are stored once, so the file is smaller and closed meshes stay closed.

Frequently asked questions

Does STL to OBJ add textures or UVs?

No — an STL has neither, so the OBJ has geometry and a plain material only.

Is my file uploaded?

No. Everything runs in your browser.