Online STL viewer
Open any binary or ASCII STL file in a fast 3D viewer, right in your browser. See its dimensions, volume, surface area and triangle count, check whether the mesh is watertight, and get a print cost estimate below.
- File
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- Size (X × Y × Z)
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- Volume
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- Surface area
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- Triangles
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- Mesh check
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- Build volume
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Cost estimate
| Cost | How | Amount | Share |
|---|
Printer, time & electricity
Labor, failures & markup
Viewer controls
| Rotate | Drag with the mouse or one finger |
|---|---|
| Zoom | Click the model, then use the scroll wheel; pinch on a trackpad or touch screen; or + and − keys |
| Preset views | 3D, Front and Top buttons |
| Reset | Double-click, or press 0 |
| Keyboard | Focus the model and use the arrow keys |
What the viewer checks
Every file is checked as it opens. Identical vertices are welded and each edge is counted: in a closed, printable mesh every edge is shared by exactly two triangles running in opposite directions. The viewer reports open edges (holes), non-manifold edges (three or more faces on one edge), flipped faces and the number of separate parts. Back faces are drawn in red, so holes and inverted normals are easy to spot.
It also compares the model with the build volume of the printer type you choose and tells you the largest scale that fits. If the model looks like a speck, change File units: STL files have no units, and models exported in metres or inches are common. Read more in STL files explained, or see how to open STL files on Windows, Mac, iPhone, Android and Linux.
Private by design
Your STL is parsed with JavaScript and drawn with WebGL on your own device. Nothing is uploaded, so unreleased designs and customer files stay private, and large files open without waiting for a transfer.
FAQ
Which STL files are supported?
Binary and ASCII STL, including binary files whose header starts with the word “solid”, which trips up many simple readers. Files with millions of triangles open in seconds on a modern computer.
Can I view 3MF or OBJ files?
Not yet — export the model as STL from your slicer or CAD program. 3MF support is on our roadmap.
Why are parts of my model red?
Red shows the inside (back faces) of the mesh. If you can see red from outside, the model has holes or flipped triangles.