Min-ji Kim
crazy how much smaller the file is. thanks!
STL to 3MF Converter: Free & Online
Prepare and convert mesh files from STL to 3MF format for precise 3D printing.
- Free
- No sign-up
- No install
Open .stl → Export → choose .3mf
Click Open Files and pick your .stl file. Then click Export, choose .3mf in the Extension list and click Save.
How to convert STL to 3MF
Open your .stl file
Click Open Files in the converter above and pick the file on your computer. It opens in your browser, with no sign-up.
Export as .3mf
Click Export and choose .3mf in the Extension list. The list starts at .mrmesh, the native MeshInspector format.
Save the file
Click Save. The .3mf file downloads to your computer.
In the desktop app
- Install and sign in. Download MeshInspector for Windows, macOS or Linux and sign in. The free Community plan is enough.
- Open the file. Click Open Files and pick the .stl file.
- Export. Select the model, click Export and choose .3mf.
- Save. Pick a folder and save the .3mf file.
What to know about STL → 3MF
- STL is a bare triangle mesh without units; 3MF is a ZIP package around an XML model that records units and can carry colors and several objects.
- Converting STL to 3MF adds no colors or textures: the 3MF holds the same triangles as the STL.
- STL has no units, so check the size of the model in your slicer after conversion, and use Scale if it is off by a factor of 10, 25.4 or 1000.
- Slicers open 3MF as well as STL; 3MF keeps the file as one package instead of loose triangles.
- If the STL has holes or flipped triangles, fix them before export: Fill Holes and Flip Normals are free tools.
Online or desktop
Online
The converter on this page runs the MeshInspector web app in your browser: no install, no sign-up. It suits single files; the web app works within your browser's memory.
Desktop
The desktop app runs on Windows, macOS (Apple silicon) and Linux. Use it for large files, many files, and the tools the web app does not have. The free Community plan covers opening and exporting; see Pricing for what the paid plans add.
FAQ
Do I need an account to convert STL to 3MF?
No. The converter on this page is the MeshInspector web app running in your browser without sign-up. Click Open Files and pick your .stl file, select it in the scene list, click Export, choose .3mf in the Extension list and click Save. The converted file downloads to your computer.
Is the STL to 3MF converter free?
Yes. Opening a .stl file and exporting it as .3mf use free tools, here, in the web app and in the desktop app on the free Community plan. Paid plans add tools such as Mesh Healer and automatic repair; the Pricing page lists what each plan includes.
Are colors and units kept?
3MF records units, while the source format may not, so check the size of the model after conversion. 3MF can carry colors and several objects, but the export writes the mesh geometry of the selected object, so check the result in your slicer before printing.
Is there a file size limit?
There is no fixed limit on this page, but the web app works within your browser's memory: up to about 4 GB, or 16 GB in browsers with 64-bit WebAssembly. For very large models, or many files, use the desktop app for Windows, macOS or Linux.
Free Community planWindows, macOS (Apple silicon) and Linux
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By Mesh Inspector TeamPublished: Updated:
