Check the OBJ before converting
OBJ coordinates are treated as millimetres here, and textures or MTL libraries are not used. Confirm that the mesh is the model you intend to convert.
CADProps · CAD tools
Convert OBJ to STL Online: Mesh to Mesh
Convert an OBJ triangle mesh to STL. Check scale and whether the mesh is closed; the result is not a CAD solid.
No account required
Temporary workspaceCAD processingBefore you use the result
Know what you are looking at.
Convert OBJ to STL for a mesh workflow that expects STL. Verify units yourself. The conversion does not repair holes or create engineering geometry.
Convert OBJ to STL
Choose STL and download the triangles. The file remains a mesh. It does not gain a unit declaration or a CAD feature history.
Verify closure and scale
A known dimension confirms scale. Volume is approximate and only meaningful for a closed, consistent mesh. An open OBJ does not become a watertight solid because it was saved as STL.
Questions about this task
Know the limits.
Can I convert OBJ to STL online?
Yes. Upload an OBJ file, choose STL and download the mesh.
Will the STL file be a closed solid?
Only if the OBJ mesh was already a closed, consistent shell. Conversion does not fill holes or rebuild CAD solids.
How are OBJ units handled?
OBJ does not declare reliable units. CADProps assumes millimetres. Check one known dimension after conversion.
Related reading
Checks that help with this file.
MeasurementOBJ Mesh Units and Volume: Check Scale and a Closed Shell
OBJ does not declare reliable units. See how millimetres are assumed, when mesh volume is only an approximation, and why OBJ is not a CAD solid.
Read the guide →
MeasurementDo STL Files Have Units? How to Fix mm vs Inch Scale
Understand why STL coordinates do not reliably declare physical units, diagnose mm-versus-inch scale errors, and verify dimensions before printing or manufacturing.
Read the guide →TroubleshootingSTL Volume Zero or Missing? Check the Mesh Is Closed
Diagnose STL files with zero, missing or unreliable volume by checking watertightness, inconsistent faces, units and export quality before calculating mass.
Read the guide →