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STL to 3MF converter

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

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

STL vs 3MF— what's the difference?

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
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

How to convert STL to 3MF

  1. 1
    Drop a .stl file onto the page. Binary or ASCII STL both parse. Nothing leaves your browser.
  2. 2
    Confirm the mesh looks right in the preview — orient, zoom, inspect the triangle count.
  3. 3
    Click Download .3MF. Load it directly in Bambu Studio, PrusaSlicer, Cura, or OrcaSlicer.

FAQ

Why convert STL to 3MF?

3MF is the modern replacement for STL in 3D printing. It carries real-world units, colour, multi-material bodies, and metadata — STL carries none of that. Every current slicer (Bambu Studio, PrusaSlicer, Cura, OrcaSlicer) prefers 3MF when it is available.

Will my STL lose precision converting to 3MF?

No — 3MF stores the same triangle mesh STL does, so the geometry is bit-identical. The gain is on the metadata side: units, model info, and multi-body packaging.

Can I set units during conversion?

STL has no units, so the converter assumes the numbers are millimetres (the 3D-printing default). If your STL was authored in inches, scale it in your slicer after importing the 3MF.

Will the 3MF be smaller than the STL?

Usually yes — 3MF zips its XML payload, so a typical binary STL shrinks 30–60% when re-packaged as 3MF.

Is anything uploaded?

No. The STL is parsed in your browser and re-packaged as 3MF locally. The file never touches a server.

Related converters

STL → OBJSTL → GLBOBJ → 3MFSTEP → 3MF3MF → STL