Convert 3MF to STL
Free · no signup · no watermark · runs in your browser · batch up to 20 files, download as ZIP
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This free 3MF to STL converter turns your .3mf models into .stl files. 3MF is the modern 3D printing format: one zipped file with real units, multiple objects and colours, read by PrusaSlicer, Cura, Bambu Studio and Windows.
This conversion runs entirely in your browser. The file is never uploaded, which makes it instant, private and usable on work files you would not want to send to a stranger's server.
It also works as a bulk 3MF to STL converter: drop up to 20 3MF files at once, they are converted one after another in your browser, and you can download each file on its own or all of them together in a single ZIP. A file that fails is listed with the reason and does not stop the rest of the batch.
How to convert 3MF to STL
- Drop your 3MF files onto the box above, or click it to choose from your computer. Up to 20 at once.
- Check the 3D preview and model info. If the model is the wrong size or lying on its back, open the options to set the source units or rotate Z-up to Y-up, then press Convert.
- Download each converted file from the list, or press "Download all (.zip)" to get the whole batch in one ZIP file.
What changes when you convert 3MF to STL
STL stores triangles only, so any colours, materials, textures, UVs and animation in the 3MF file are dropped. The geometry itself is kept exactly.
STL has no units. The converter writes millimetres by default (and Z-up for STL and PLY), which is what slicers and CAD tools expect; change it under the options if you need something else.
3MF and STL compared
| 3MF | STL | |
|---|---|---|
| Full name | 3D Manufacturing Format | Stereolithography |
| Extension | .3mf | .stl |
| MIME type | model/3mf | model/stl |
3MF: The modern 3D printing format: a zipped XML package with declared units, multiple objects and colours. Read by PrusaSlicer, Cura, Bambu Studio, OrcaSlicer and Windows 3D Builder.
STL: The 3D printing workhorse: a list of triangles and nothing else. No colour, no materials, no UVs and no units (millimetres by convention), which is why every slicer and CAD tool can read it.
Frequently asked questions
How do I convert 3MF to STL?
Drop your .3mf file onto the box on this page and the .stl file is ready to download in a second or two. There is no signup, no email, no watermark and no file limit beyond what your browser can hold in memory.
Is this 3MF to STL converter free?
Yes, completely, with no account, no trial and no watermark on the output. There is nothing to buy on this page: choose a file, convert it and download the result.
Are my files uploaded anywhere?
No. This conversion runs entirely in your browser using JavaScript, so the file never leaves your computer. You can disconnect from the network after the page loads and it will still work.
Will converting to STL reduce the quality?
STL stores triangles only, so any colours, materials, textures, UVs and animation in the 3MF file are dropped. The geometry itself is kept exactly.
Can I convert multiple 3MF files to STL at once?
Yes, up to 20 files in one go. Drop or select them all together and they are converted one after another. Each file appears in the results list with its own download button, and "Download all (.zip)" saves the whole batch as a single ZIP. If one file cannot be converted, it is listed with the reason and the others still finish. For more than 20, run a second batch.
Found a problem, or something that could be better? We read every message and we fix things quickly.
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