STL Viewer
An STL viewer for checking a print before it costs you filament: open any .stl file in your browser, orbit it, read its bounding-box size in centimeters or millimeters, and confirm it looks right — the file never leaves your device.
Your files never leave your device · No sign-up · FreeThe file is opened locally in your browser. It is never uploaded.
File: No model loaded
Load a model to see its dimensions.
What is an STL file?
STL (stereolithography) is the standard mesh format for 3D printing. It stores only surface geometry — a shell of triangles with no color, material or unit information. Almost every slicer accepts it, which makes it the format to double-check right before printing.
The pre-print sanity check
Three things are worth ten seconds before a long print: the overall size (shown here from the bounding box), the orientation the part was exported in, and the mesh itself in wireframe mode, where flipped or broken shells are easy to spot. Catching a model exported at 10× scale in the viewer is free; catching it on the build plate is not.
Frequently asked questions
How do I view an STL file online?
Drop the .stl onto the viewer above. It renders in your browser with orbit controls — drag to rotate, scroll to zoom — and its dimensions appear in the panel.
What units are STL dimensions in?
STL files store raw numbers with no unit. This viewer displays them assuming 1 unit = 1 cm and can relabel the same numbers as millimeters. Most slicers assume millimeters, so confirm the size in your slicer before printing.
Does the viewer repair broken STL files?
No, it is an inspection tool: it shows the mesh exactly as stored, including in wireframe mode, so you can spot problems. Repair belongs in your modeling tool or slicer.
Is my STL uploaded?
No. The file is read and rendered locally in your browser tab; there is no upload and no stored copy.
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