# Convert STL to OBJ Online: Mesh to Mesh

Convert an STL triangle mesh to OBJ. The conversion does not recover a precise CAD solid or add reliable units.

Convert STL to OBJ when another mesh tool expects OBJ. Both files are triangles. This does not turn a mesh back into a STEP solid.

## Treat the STL as a mesh

STL has no reliable unit declaration. CADProps measures STL coordinates as millimetres. Confirm a known dimension before converting if the scale matters.

## Convert STL to OBJ

Choose OBJ and download the mesh. The triangles are copied into OBJ. Materials, textures and a CAD feature tree are not created.

## Do not expect a solid

An open or inconsistent STL stays a mesh. Volume, if shown, is an approximation and only applies to a closed, consistent mesh. Use the original CAD or STEP file when you need an exact solid.

## Questions

### Can I convert STL to OBJ online?

Yes. Upload an STL file, choose OBJ and download the mesh.

### Will STL to OBJ create a STEP solid?

No. OBJ is still a triangle mesh. Converting the mesh does not reconstruct precise CAD curves or a solid model.

### Does the OBJ file gain units?

No. Neither STL nor OBJ declares a reliable unit. CADProps assumes millimetres when it measures these meshes.

## Related guides

- [OBJ Mesh Units and Volume: Check Scale and a Closed Shell](https://www.cadprops.com/guides/obj-mesh-units-and-closure/index.md)
- [STL Volume Zero or Missing? Check the Mesh Is Closed](https://www.cadprops.com/guides/why-stl-volume-is-zero/index.md)
- [Do STL Files Have Units? How to Fix mm vs Inch Scale](https://www.cadprops.com/guides/stl-files-have-units/index.md)

## Related tools

- [STL viewer](https://www.cadprops.com/tools/stl-viewer/index.md)
- [OBJ viewer](https://www.cadprops.com/tools/obj-viewer/index.md)
- [OBJ to STL](https://www.cadprops.com/tools/obj-to-stl/index.md)

HTML page: https://www.cadprops.com/tools/stl-to-obj/