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Your STLs are converted and packed on your own computer and never uploaded. Each file can be up to 300 MB.
STL to 3MF Converter
Turn STL files into compact 3MF, or pack a batch of parts into one project for Bambu Studio and PrusaSlicer.
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Files
Converted in your browser. Files are never uploaded.
Continue with your project
Open the 3MF to confirm every part is there, or check an STL before you pack it.
How to convert STL to 3MF
- 1
Add STL files
Drop one STL or every part of a project.
- 2
Pack or keep separate
Write one 3MF per STL, or choose All in one 3MF to get a single file with every part as an object.
- 3
Open in your slicer
The 3MF opens in Bambu Studio, PrusaSlicer, OrcaSlicer and Cura with millimeter units set.
Why use this STL to 3MF converter
Built for turning loose STL files into slicer-ready 3MF projects.
Size shown before you convert
Each STL sits on a build plate with its size in millimeters or inches, so a part saved in inches shows up tiny before it reaches the slicer.
Resize the longest side
Enter a length in millimeters and each model is scaled so its longest side matches before the 3MF is written.
Laid out on the plate
Packed models are placed in rows 10 mm apart and centered, so they open side by side in your slicer instead of on top of each other.
Why 3MF beats STL for projects
3MF is a zipped, unit-aware format that can hold many objects. Converting gains you structure without changing the shape.
Kept
- Every triangle, with shared vertices
- Millimeter units written into the file
- One named object per STL when packing
- Smaller files thanks to ZIP compression
Left behind
- Print settings, which you add in the slicer
- Original positions (packed models are laid out in rows)
- Colors and filament assignments
- Supports and modifiers
STL to 3MF questions
Answers about packing parts, Bambu Studio, file size and cost.
Why convert STL to 3MF?
3MF stores units, so there is no guessing between millimeters and inches, and it compresses well. It also lets you send several parts as one file.
Can I combine several STLs into one 3MF?
Yes. Add them all, choose All in one 3MF, and each STL becomes its own object in the project.
Will Bambu Studio open the file?
Yes. The 3MF follows the core specification that Bambu Studio, OrcaSlicer, PrusaSlicer and Cura all read.
Is the file smaller than the STL?
Usually, yes. Shared vertices and ZIP compression often make the 3MF a third to a half of the binary STL's size.
Is the STL to 3MF converter free?
Yes. It is free with no sign-up, and files are converted in your browser.