STL Repair Tool Online — Free, Browser-Side, No Upload
STL → repaired STL
Repair common STL mesh issues in your browser. Rebuild normals, remove degenerate triangles, and download a cleaned STL file.
Best for
- Cleaning STL files that contain zero-area or duplicate-style broken triangles
- Rebuilding face normals before importing a mesh into a slicer
- Trying a quick browser-side repair pass before opening Blender or Meshmixer
- Handling private printable models without uploading them to a repair service
Before you start
- Use this for basic cleanup, not for reconstructing missing surfaces or design intent
- Run a slicer check after download because non-manifold problems may remain
- Keep the original STL in case a stronger mesh editor is needed
- Confirm scale after repair because STL still has no unit metadata
Known Limitations
- Beta repair only — complex non-manifold meshes may still need a dedicated mesh editor
- The tool removes invalid or zero-area triangles and rebuilds normals; it does not reconstruct missing design intent
- STL has no units, materials, or textures; repaired output remains geometry-only
Helpful guides
Frequently Asked Questions
What mesh problems does this tool fix?
The tool removes degenerate (zero-area) triangles and rebuilds face normals so they all point outward. This addresses the most common reasons slicers like PrusaSlicer and Cura report errors on import.
Will it fix non-manifold edges and holes in my mesh?
This is a basic repair pass — it handles normals and degenerate triangles. Non-manifold edge repair and hole-filling are not available in this tool. For complex geometry, Meshmixer or Blender are the right tools.
Does the repair change my model geometry?
The tool removes only invalid triangles (zero area or with coincident vertices) and does not move or add vertices. Geometry that is already valid is untouched.
Does my STL file get uploaded to a server?
No. All repair processing runs in your browser. Your file never leaves your device — no upload, no cloud storage.
My slicer still reports errors after repair. What should I do?
If the repaired STL still has issues, the mesh likely has non-manifold edges or topological problems that require a full mesh editor. Try Meshmixer (free) or Blender for a more thorough repair.
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How it works
Your files are processed entirely inside your browser using Three.js. Your files never leave your browser — there is no server upload, no cloud storage, and no third-party processing. The converted file is generated as a local Blob and downloaded directly to your device. Once the conversion is complete, all data is released from memory.