Online STL Viewer
Drop an STL file to view it in 3D, check its dimensions and estimate how much filament it needs. It works in your browser: nothing is uploaded.
How to open an STL file online
- 1
Drag your STL file onto the box above, or click it to choose a file.
- 2
Rotate the model by dragging, zoom with the mouse wheel or a pinch, and pan with the right button or two fingers.
- 3
Switch between front, top, right and isometric views, turn the wireframe and the grid on or off, and change the model color.
- 4
Read the dimensions, volume, surface area and estimated weight in the measurements panel, in millimeters, centimeters or inches.
- 5
Save a PNG image of the current view to share it or add it to your documentation.
What is an STL file?
STL (stereolithography) is the most common file format for 3D printing. It describes the surface of a 3D object as a mesh of triangles, without colors, textures or units.
STL files come in two flavors: binary, which is compact and the most common, and ASCII, which is plain text and easier to read. This viewer opens both.
How the measurements are calculated
The dimensions are those of the bounding box: the smallest box aligned with the X, Y and Z axes that contains the whole model.
The volume is calculated exactly from the triangles of the mesh, so it is reliable for closed (watertight) models, which is what slicers expect. The estimated weight assumes a solid part printed in PLA (1.24 g/cm³); real prints usually weigh less because of the infill.
STL files do not store units. Like almost every 3D printing program, this viewer assumes the values are in millimeters.
Is it safe?
Yes. The file is read by your own browser and is never sent to any server, so you can open confidential parts without worrying.
Frequently asked questions
Is this STL viewer free?
Yes. You can open, view and measure STL files for free, with no account and no limits on normal use.
Are my files uploaded to a server?
No. The STL file is processed entirely in your browser and never leaves your device.
Can I open large STL files?
Yes. Files with millions of triangles are read in the background so the page stays responsive. The limit depends on the memory of your device.
What units does the viewer use?
STL files have no units, so millimeters are assumed. You can show the measurements in millimeters, centimeters or inches.
Does it work on phones and tablets?
Yes. It works in any modern browser on computers, phones and tablets, with touch gestures to rotate and zoom.