Free 3MF (.3mf) to STL (.stl) converter — running entirely in your browser. No upload, no signup, no file limits: your files never leave your device.
STEP · IGES · BREP · STL · OBJ · PLY · GLB · glTF · 3MF · COLLADA · AMF · FBX · 3DS · OFF · LAS · PCD · XYZ · PTS
3MF is the modern replacement for STL, backed by the 3MF Consortium (Microsoft, HP, Autodesk, Prusa and others). It stores watertight meshes together with units, colors, materials and print settings in one ZIP-based file, and current slicers increasingly prefer it over STL.
STL is the de-facto standard for 3D printing. It describes a model purely as a mesh of triangles — no color, no units, no assembly structure — which makes it simple, universally supported, and the required input for virtually every slicer, from PrusaSlicer and Cura to resin-printer tools.
| 3MF | STL | |
|---|---|---|
| Geometry | Watertight triangle mesh | Triangle mesh |
| Units | Yes, required by spec | No — unitless numbers |
| Colors & materials | Colors & materials | No |
| Animations | No | No |
| Typical use | Modern 3D printing | 3D printing |
Yes — free with no accounts, no watermarks and no file-size limits. Conversion runs on your own machine, so there are no server costs behind it.
No. The converter runs entirely in your browser using WebAssembly. Your .3mf file never leaves your device, which makes it safe for confidential designs.
Yes — parts and assembly hierarchy are preserved where STL supports them, and you can optionally merge everything into a single mesh during conversion.
Yes. Every converted model opens in the built-in 3D viewer with an assembly tree, display modes and section views, so you can inspect the result first.
3MF can describe richer materials than this neutral mesh pipeline keeps. Geometry, part structure and a flat part color can survive, but texture and multi-material detail cannot. The STL result also has no units, colors, material data or part names, so keep the source alongside it.
Which file format should you actually print from? A practical ranking of STL, OBJ, 3MF and AMF for FDM and resin printing, with free conversion tools.
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