How to open an STL file without software

Updated 28 October 20263 min read

Quick answer

Open the 3D model viewer and choose the file. You can turn it, zoom in and see its size straight away. Nothing is installed and the file isn’t uploaded.

3D model viewerFree, no sign-up, and your files never leave your device.

Open the tool

Step by step

Open the 3D model viewer.
Choose or drop the STL file (OBJ, PLY, GLB and FBX work too).
Drag to turn it and scroll or pinch to zoom. If it is lying on its back, tick Stand upright.
Check the size and Watertight lines under the view. Select Save picture for a PNG of the view.

Which 3D format should I use?

STL is the standard for 3D printing: shape only, no colours. OBJ is understood by almost every 3D app. GLB is the standard for the web, AR and games, and keeps colours and textures in one file. USDZ is what iPhones and iPads use for AR.

Tips

STL files don’t store units. Models made for 3D printing are almost always in millimetres.
Watertight means the surface has no holes. 3D printers and slicers need a watertight model.
To use the model in AR on an iPhone, convert it to USDZ, choosing Stand upright and Millimetres to metres.

If something goes wrong

It says the GLB refers to separate files.

Export it again as a single, self-contained GLB (in Blender: glTF Binary).

Nothing shows, or it says my browser can’t show 3D.

Your browser has 3D graphics (WebGL) turned off. Try another browser. 3D model information still measures the model without showing it.