STL viewer
To open an STL file, drop it in the box below. It opens straight away, even with no extension or the wrong one. Your browser opens it on your device: nothing is uploaded.
Open in
Opened on this device, never uploadedDrop or paste another file at any time
What you see
| STL in the viewer | |
|---|---|
| Read | Binary and ASCII STL, colours some exporters add |
| Watertight | Checked: every edge joins two triangles |
| Details | Triangles, size, parts |
| Next | Convert to OBJ, PLY or GLB |
| Extensions | .stl |
| Upload | None: opened on your device |
What is an STL file?
In short
STL is the file format of 3D printing: a model’s surface as triangles, without colour or units.
The model in a 3D view you can turn, pan and zoom, with its triangles on a switch. Details lists the triangles, size and whether it is watertight (ready to slice).
How to open an STL file
- Add your STL. Drop the file in the box, choose it or paste it.
- Look at it. The model in a 3D view you can turn, pan and zoom, with its triangles on a switch. Details lists the triangles, size and whether it is watertight (ready to slice).
- Take it further. Open in hands it, in a new tab, to File converter or Batch.
Questions
Drop it here: it opens in a 3D view on your device, and Details says whether it is watertight.
Every edge is shared by exactly two triangles, so the model encloses a volume. Slicers need that to print it.
No. The viewer runs in your browser and opens the file on your device. Nothing is sent anywhere.