Check and repair your 3D file in 30 seconds, free
Find holes, flipped faces and unit mistakes before they ruin a print, see exactly where they are, and fix them in one click. Your file never leaves your browser.
Drag a 3D file here or click to choose
STL · OBJ · 3MF · PLY · STEP · up to 100MB
Your file is analyzed only in your browser and is never sent to or stored on our servers.
Holes & open edges
Missing faces make volume and printing inaccurate.
Non-manifold edges
Edges shared by three or more faces can confuse the slicer.
Flipped faces
Inside-out faces may fail to print or fill in hollow areas.
Size, units & printer fit
Spot unit mistakes and parts too large for any printer.
STL checker FAQ
Is my file uploaded to your server?
No. The check runs entirely in your browser and the file is never sent to or stored on our servers. It is used only if you choose to get a quote.
What does it check?
Holes (open edges), non-manifold edges, flipped faces, separate shells, zero-area triangles, size and unit mistakes, and whether the part fits each printer. Wall thickness and self-intersections are reviewed by our team after you request a quote.
Can a file with errors still be printed?
Small holes and flipped faces are usually corrected automatically during print preparation. Large holes can make the volume and price inaccurate, so we recommend running auto repair before getting a quote.
Can it fix STL errors automatically?
Yes. Click 'Run auto repair' in the results to fill holes, close tiny gaps, remove duplicate and internal faces, unify face orientation and remove tiny loose fragments right in your browser, then compare the before and after results. It works like the automatic repair in Bambu Studio or PrusaSlicer; self-intersecting faces are not covered.
How do I get the repaired file?
Anyone can run the repair for free, and downloading the repaired STL is free for logged-in members. Your repair result is kept when you return after logging in, and 'Get a quote for the repaired file' takes you straight to pricing without re-uploading.
Can it check STEP files?
Yes. STEP/STP files are converted to a mesh in your browser and checked the same way. STEP files exported straight from CAD usually have very few errors.