View an STL file in your browser
Drop in an .stl file and look at it in 3D — spin it, zoom in, and read off its triangle count and bounding-box dimensions. This is a viewer, not a converter: nothing about the mesh is changed.
Your file is opened and rendered entirely in this browser tab. It never leaves your computer and is never sent to a server.
How it works
Good to know
FAQ
What units are the dimensions shown in?
STL files don't store units — the format is just raw numbers. We display the bounding box in those raw numbers, and almost every 3D-printing and CAD workflow treats them as millimeters. So a box reported as 40 x 20 x 10 is almost certainly 40 x 20 x 10 mm, but the file itself can't confirm that. If a model looks 25.4x too big or too small, it was likely exported in inches.
Will this show the color, material, or texture of my model?
No — and that's a limitation of STL, not of this viewer. An STL stores only triangles (the surface shape). It carries no color, material, or texture data, so we render it in a single neutral shade. If you need color or materials, you're looking for a format like 3MF, OBJ+MTL, or glTF, not STL.
Does my file get uploaded anywhere?
No. The file is read and rendered by JavaScript inside this browser tab. There's no server upload, no account, and nothing is stored after you close or refresh the tab. You can confirm this by opening your browser's network panel — you won't see your model being sent out. This also means it works offline once the page has loaded.
How big an STL can it open?
It comfortably handles typical print files (tens of MB, a few million triangles). Because everything runs in your browser, the real ceiling is your device's RAM and graphics, not an upload limit — very large meshes (hundreds of MB) may load slowly or strain a low-end machine. Binary STLs are far smaller and faster to open than ASCII STLs of the same model.
Can I tell from here whether the model will 3D-print correctly?
Only partly. You can eyeball the shape, check overall dimensions, and spot obvious problems. But this viewer doesn't check for non-manifold edges, flipped normals, holes, or wall thickness — for print-readiness you'll want your slicer or a mesh-repair tool. Treat this as a quick look, not a pre-print validation.
What's the difference between this and an STL-to-STEP converter?
A viewer just shows you the mesh. Converting STL to STEP is a different, harder problem — STL is a triangle mesh and STEP is solid CAD geometry, so going between them isn't a clean export. If that's what you need, see our STL-to-STEP page, which explains honestly what is and isn't possible rather than promising a one-click conversion.