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3MF to STL converter

Drop your .3mf file — we convert it to .stl right in your browser. Files never leave your computer.

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Drop your 3MF file here
Accepts .3mf · converts to .stl

3MF vs STL— what's the difference?

3MF.3mf

Modern successor to STL for 3D printing — carries units, colours, materials, and multiple bodies in a zipped XML package.

Strengths
  • Real-world units baked in (no more "is this mm or inches?")
  • Multi-material, multi-colour, and per-body metadata
  • Compact zipped payload — smaller than equivalent STL
Limitations
  • Not every slicer reads 3MF yet (most do now — Bambu, Prusa, Cura)
  • Less tooling for mesh editing compared to STL
Typical use: Modern 3D printing workflows, multi-material prints
STL.stl

Triangle-mesh format that every 3D printer slicer understands. Geometry only — no units, colours, or assemblies.

Strengths
  • Universal 3D printing format — Cura, PrusaSlicer, Bambu Studio all speak STL
  • Tiny, simple, extremely fast to load
  • Great for meshing workflows, simulation pre-processors, quick previews
Limitations
  • Triangulated approximation — curved surfaces lose precision
  • No colour, material, or assembly data
  • One shell per file by convention (multi-body gets flattened)
Typical use: 3D printing, rapid prototyping, mesh-based workflows

How to convert 3MF to STL

  1. 1
    Drop a .3mf file. Multi-body 3MFs are fine — all bodies get packed into one STL.
  2. 2
    Preview the model in 3D. Check the Scene Tree to confirm every body is included.
  3. 3
    Click Download .STL. Open in any slicer, even old ones that don't read 3MF.

FAQ

Why go 3MF → STL? 3MF is newer and better.

Agreed — for modern workflows, keep 3MF. Convert when: your slicer is old, you're sending to a print service that only accepts STL, or you need to edit in a tool that doesn't read 3MF yet.

Will multi-material / multi-colour data survive?

No. STL carries geometry only. Colours, materials, and per-body metadata from the 3MF are dropped. If colour matters, keep the 3MF.

What about units?

3MF stores real-world units; STL does not. We preserve the numeric coordinates so the resulting STL is the correct size if your slicer assumes millimetres (which most do).

Multi-body 3MFs — does each body become a separate STL?

No, they get merged into one STL file (STL has no multi-body concept). If you need per-body STLs, split the bodies in your CAD / slicer first.

Is my 3MF uploaded anywhere?

No. Three.js' 3MFLoader unpacks the zip in your browser and the STL is re-exported locally.

Related converters

STL → OBJSTL → GLBSTEP → STLOBJ → STL