STL Repair Tool is a free tool. Upload an STL file for STL repair, fix holes, flipped faces and duplicate points automatically, then download the result; no sign-up needed.
Runs in your browser · your file is not uploaded · no sign-in needed
Configure your options
Your 3D Model Will Appear Here
Fill in the options on the left, then press the button. The work is done in your browser.
Relevant internal links based on this tool
Upload your image
Drag & drop your file here or click to browse
STL repair checks a model file for common print problems and fixes what can be fixed automatically, such as small holes, flipped faces, duplicate points and zero-area triangles. It suits anyone whose slicer rejects a file or warns about a broken mesh. Upload your STL, run the check, and download the repaired file along with a report of what changed. It runs fully in your browser, so no sign-up and no credits are used.
Use the Upload an STL File field to add the model your slicer flagged as broken or that failed to print correctly.
Press Repair STL and let the tool scan for duplicate points, zero-area triangles, flipped faces and small holes automatically.
Read the report of what was found and changed, then download the repaired file and try slicing it again.
If your slicer warns about a non-manifold mesh or refuses to generate supports properly, running the file through a repair check often clears common issues like small holes or flipped faces.
AI-generated meshes from a photo-to-3D process often have small holes or thin spots, so a repair pass before printing can close simple gaps that would otherwise show up as defects.
Badly damaged or self-intersecting models may still need a desktop repair tool, so check the report after running this tool to see whether the remaining issues need further work.
It checks for and fixes duplicate points, zero-area triangles, flipped faces and small holes, then gives you a report of what was found and what was changed in the file.
No. It runs fully in your browser, so no account is needed and no credits are used, and the file is never uploaded to a server.
Not every file. Badly damaged or self-intersecting models may still need a desktop repair tool, since some problems go beyond what automatic repair can safely fix.
Holes often come from scanning or generation processes that could not see every angle of an object, or from manual editing that leaves gaps in the mesh surface.
A non-manifold mesh has edges or vertices shared by more than two faces in a way that does not describe a real solid, which confuses slicers trying to calculate a printable interior.
Repair the file first, since fixing holes and flipped faces works on the mesh geometry directly, and scaling afterward does not reintroduce the problems that repair already fixed.
Make direct edits to your mesh after the automatic repair is done.
Open the repaired file to confirm it looks correct before printing.
Convert a 3MF file to STL if that is the format your slicer needs.
Turn a different photo into a printable lithophane panel instead.
Your file stays on your device. It is not uploaded.