Convert OBJ to STL online
OBJ files from 3D programs usually use metres or centimetres with Y pointing up, slicers expect millimetres and Z-up. The converter reads the OBJ in the unit you choose, writes one binary STL in millimetres and checks it for holes.
Your files never leave your device
Drop a file to see it here.
Drop to add
How it works
- Drop the .obj file. The MTL file and textures are not needed for STL.
- Choose the unit the OBJ was made in and keep the 3D printing preset on.
- Convert, check the dimensions and the watertight result, then download the STL.
What is kept and what to watch
- All objects and groups of the OBJ are merged into one STL.
- Materials, UVs and textures are not part of STL and are left out.
- Quads and polygons are split into triangles when the OBJ is read.
Other conversions
Frequently asked questions
Which unit is my OBJ in?
OBJ has no unit field. Blender exports metres by default, many other programs use centimetres. Compare the dimensions in the info panel with the real object and set the source unit.
Why does the check report open edges?
The mesh has holes or separate surfaces that do not touch. Many OBJ models for games are built that way. Repair them in your slicer or mesh tool.
Does the converter change the geometry?
No. The triangles are written as they are, only scaled, rotated and moved as set in the options.