Converters · STL → 3MF
STL to 3MF Converter
Free, private, in your browser. Convert STL to 3MF — no signup, no upload.
Unlike online converters that upload to a server, your file never leaves your browser.
⇄ Need 3MF to STL instead?Drop your 3D file here
or click to browse — .stl files up to 200 MB
When to convert STL to 3MF
You have an STL — from a print library, a CAD export, or an older tool — and need a 3MF, the format Bambu Studio and PrusaSlicer save by default. Drop the STL above for a clean 3MF container, geometry intact, entirely in your browser.
STL vs 3MF: what’s the difference?
STL is the 1987 standard: a bare list of triangles with no color, no units and no UV, understood by every slicer and CAD tool. 3MF (3D Manufacturing Format) is the modern, zip-based container that can hold geometry together with color, materials and print settings — what Bambu Studio and PrusaSlicer save by default. Converting STL to 3MF wraps your triangles in that modern container. Because an STL never carried color or materials, the 3MF you get holds geometry only — there is simply no appearance data in the source to bring across.
What STL → 3MF keeps and drops
Preserved
- ✓Every triangle of the geometry, exactly
- ✓Real-world scale and dimensions
- ✓Model orientation
Dropped
- ✗No color or materials — STL never stored any, so the 3MF has none to carry
- ✗No print settings, supports or plate layout — add those in your slicer
- ✗Nothing else: the geometry is copied as-is
How to convert STL to 3MF
- 1Drop your .stl file onto the box above, or click to browse.
- 2The file is parsed in your browser — nothing is uploaded.
- 3Check the 3D preview, then click “Convert to 3MF”.
- 4A .3mf file downloads, ready to open in Bambu Studio or PrusaSlicer.
This 3MF is geometry only — converting from STL cannot add color, because the STL never had any. If you want a full-color 3MF for a Bambu AMS or Prusa MMU, start from a colored source and use our GLB to 3MF or glTF to 3MF converter instead — those bake the texture into printable color. Reach for STL to 3MF when a tool or workflow specifically wants the 3MF container. Geometry is copied as-is, so if the STL has holes or non-manifold edges, run our free STL Repair before printing.
STL to 3MF — FAQ
Does converting to 3MF add color to my STL?
No — STL stores no color, so there is nothing to bake in; the 3MF is geometry only. For a color print, start from a GLB or glTF and use those to-3MF converters, which turn the texture into per-vertex color.
Why convert STL to 3MF if my slicer already opens STL?
3MF is the modern default for Bambu Studio and PrusaSlicer and travels better through newer workflows. If your slicer imports STL directly and you don’t need the 3MF container, you may not need to convert at all.
Is my STL uploaded anywhere?
No. The converter runs in your browser tab; your file never leaves your device.