Convert OBJ to STL in your browser
Both formats are openly documented plain text, so this conversion runs entirely in your tab: the OBJ vertices and faces are parsed here, polygons are triangulated and written out as ASCII STL with a computed normal per facet. Nothing is uploaded.
Short answer: Drop your OBJ file below and it converts to STL inside your browser — free, no sign-up, and the file is never uploaded.
| Converts in this browser | Yes |
|---|---|
| Cost | Free |
| From | OBJ — Wavefront OBJ |
| To | STL — Stereolithography mesh |
| Steps | 4 |
OBJ → STL converter
Runs entirely in this browser tab. Your file is never uploaded and nothing is stored.
Drop your OBJ file here
or — no sign-up required
Need a CAD/BIM specialist to modify or detail this drawing?
Stuck on CAD or 3D file cleanup? Post a drafting role specifying the source format, target format and checks you need. Agree the scope before work starts.
How it works
- 1Drop the .obj file above. Quads and n-gons are fan-triangulated, because STL stores nothing but triangles.
- 2Download the .stl and open it in your slicer, mesh tool or 3D print preparation software.
- 3Check the scale on arrival: neither OBJ nor STL declares units, so a model authored in metres can land as millimetres.
- 4If the mesh prints with holes, run a repair pass (Meshmixer, Netfabb, Blender 3D-Print toolbox) — an OBJ surface is not necessarily watertight.
What to watch out for
- Materials, textures, UVs and vertex colours are discarded: STL carries geometry only.
- Output is ASCII STL, which is larger than binary but readable and accepted everywhere. Re-save as binary in your slicer if file size matters.
- Face normals are recomputed from vertex order, so an OBJ with inconsistent winding may show flipped facets.
A plain-text mesh format listing vertices and faces — openly documented, which is why it can be read and rewritten in the browser.
The triangle-soup format every 3D printer and mesh tool reads. Openly documented in both ASCII and binary form, with no units, colours or structure.
Questions
Does the file get uploaded anywhere?
No. The parsing and writing happen in JavaScript in your own browser tab; the file never leaves your machine.
Why is my STL a different size than expected?
STL has no unit declaration at all and OBJ has none either. The numbers are carried over exactly, so you set the units when importing.
Popular CAD conversions
Related AEC calculators
File version help
- AutoCAD version converter
- Revit version converter
- Civil 3D version converter
- SketchUp version converter
- SolidWorks version converter
- 3ds Max version converter
- ArchiCAD version converter
- Tekla Structures version converter
- Inventor version converter
- Navisworks version converter
- BricsCAD version converter
- MicroStation version converter
Top freelance CAD & BIM engineers
- AutoCAD specialistspublished pay
- Revit specialistspublished pay
- Civil 3D specialistspublished pay
- Tekla Structures specialistspublished pay
- Navisworks specialistspublished pay
- ArchiCAD specialistspublished pay
- SketchUp specialistspublished pay
- SolidWorks specialistspublished pay
- 3ds Max specialistspublished pay
- Lumion specialistspublished pay
Related conversions
Drawing workflows and related work
Popular in-browser converters
Paid to draft, model or coordinate?
Browse employer-posted roles with disclosed pay and external CAD/BIM listings; check source pay, location eligibility and closing dates.