STL checker · before you print

Check an STL file online: dimensions, volume and mesh errors

Before you open your slicer, check the file: real size, triangle count, volume when it can be computed, and the defects that often cause trouble. The tool reports what it sees and never promises a part is printable.

Nothing is uploaded: everything runs in your browser.

How it works

  1. Open your STL

    Or a GLB / OBJ: the mesh is analyzed in your browser.

  2. Pick the unit

    STL files store no unit: tell the tool whether yours is in millimeters, centimeters or inches.

  3. Read the report

    Dimensions, triangles, surface, volume when the mesh is closed, open edges, non-manifold edges, flat triangles.

  4. Fix what's needed

    Each warning says what to check in your slicer or 3D software.

Frequently asked questions

Does the checker guarantee my part will print?
No. It detects measurable defects (open mesh, non-manifold edges, flat triangles, inverted normals, extreme sizes). A file with no warning can still fail: wall thickness, overhangs and supports are checked in your slicer.
Why is the volume not always shown?
Volume only makes sense for a closed, manifold mesh. Otherwise the number would be wrong, so the tool shows nothing.
Why do I have to choose a unit?
The STL format stores no unit. Most software assumes millimeters; some exports are in centimeters or inches. A GLB is in meters: the tool picks that unit for you.
Is my file uploaded?
No. The analysis runs entirely in your browser.

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