The Best STL Viewers for Windows, Mac, Android and iPhone (2026)
Free ways to open STL, OBJ and 3MF files in 2026 now that Microsoft 3D Viewer is gone: browser viewers, slicers, MeshLab, Blender and apps for phones.
By Depthue Lab3 min read
On this page (9 sections)
For years the answer to "how do I open an STL on Windows" was simple: double-click it and Microsoft 3D Viewer opened. That is changing. Microsoft deprecated 3D Viewer in February 2026 and removed it from the Microsoft Store on July 1, 2026. It keeps working where it is installed, but a new PC will not have it.
Here are the viewers worth using now, by platform and by job.
The quick answer
| You want to | Use |
|---|---|
| Look at a model right now, any computer | A browser viewer (below) |
| Check a model before printing | Your slicer |
| Measure, inspect or repair a mesh | MeshLab or Blender |
| Open CAD formats too (STEP, IGES) | FreeCAD |
| View on a phone | A browser viewer or a viewer app |
1. A browser viewer: fastest on any device
A good browser viewer needs no install and works on Windows, Mac, Linux, Chromebooks, Android and iPhone. The one below opens STL, OBJ, 3MF, PLY and GLB, reads the file on your own device, and shows the numbers you actually need before printing: dimensions, triangle count, volume, surface area and an estimate of PLA weight.
Microsoft itself recommends a web viewer, the Babylon.js Sandbox, as the replacement for 3D Viewer. It is built for glTF and GLB scenes; for print files, a viewer that reports millimetres and volume is more useful.
2. Your slicer: the viewer you already have
If you 3D print, your slicer is an excellent STL viewer. Bambu Studio, OrcaSlicer, PrusaSlicer and Cura all open STL, OBJ and 3MF, show the model on your printer's plate, measure it, and warn about problems like non-manifold edges. They are free and they tell you whether the part fits your machine.
The only downside is weight: a slicer takes longer to open than a simple viewer.
3. MeshLab: best for inspection and repair
MeshLab is a free, open-source program for processing meshes. It opens almost every mesh format, measures geometry, shows normals and holes, and has filters to clean, simplify and repair. It is the tool to reach for when a print fails and you suspect the file.
4. Blender: best if you also need to edit
Blender is a full 3D suite. As a viewer it is heavy, but it opens STL, OBJ, PLY and glTF, and its 3D Print Toolbox add-on checks wall thickness and overhangs. If you need to modify the model, Blender is free and does everything.
5. FreeCAD: best for engineering files
FreeCAD opens STL and OBJ plus engineering formats like STEP and IGES, which mesh viewers cannot. Use it when you work with CAD parts rather than sculpted models.
On a Mac
On recent macOS versions, pressing the space bar on a file in Finder (Quick Look) can preview many STL and OBJ files. For measurement, use a browser viewer or your slicer; Bambu Studio, OrcaSlicer, PrusaSlicer and Cura all have Mac versions.
On Android and iPhone
A browser viewer is the simplest route: download the STL to your phone, open the viewer in Chrome or Safari and load the file. Viewer apps exist on both stores, and many are free with ads. Check the permissions before installing one.
What to look for in an STL viewer
- Units and dimensions so you can catch an inch-versus-millimetre mistake.
- Volume to estimate material and cost.
- Wireframe to judge mesh density.
- Local processing for designs you should not upload.
If your file is a 3MF and you need an STL, see how to convert 3MF to STL.
Free tools for this job
Frequently asked questions
What is the best free STL viewer for Windows 11?
For a quick look, a browser viewer that works locally, such as the Depthue STL viewer. For printing, your slicer (Bambu Studio, OrcaSlicer, PrusaSlicer or Cura) is already an excellent viewer. For inspection and repair, MeshLab or Blender.
Is Microsoft 3D Viewer still available?
No longer as a new download. Microsoft deprecated 3D Viewer in February 2026 and removed it from the Microsoft Store on July 1, 2026. Installed copies keep working, and Microsoft points users to the Babylon.js Sandbox as a web alternative.
How do I open an STL file on my phone?
Open a browser-based STL viewer in Chrome or Safari and load the file from your phone's storage. There are also free viewer apps on Google Play and the App Store, many with ads.
Can an STL viewer show the size of my model?
Good ones do. The Depthue viewer shows X, Y and Z dimensions in millimetres or inches, triangle count, surface area and volume, and estimates the weight of PLA at full infill.
