STL to 3MF Converter
Convert STL to 3MF right in your browser. Fast, private, and free.
Click to upload STL files
Multiple files supported
What Does Converting STL to 3MF Achieve?
Project Packaging
Bundle multiple parts into a single .3mf file for easier versioning and sharing.
Defined Units
3MF carries an explicit unit (e.g., millimeters), reducing scale ambiguity when moving between apps.
Room for Metadata
While STL has geometry only, 3MF supports extra metadata your downstream tools can leverage.
Common Use Cases
Slicer-Friendly Project Files
- Keep parts organized as one file for team collaboration.
- Attach print notes, orientations, and draft settings in one place.
- Reduce the chance of missing parts when sharing.
Clean Handoff to Modern Pipelines
- Adopt a unit-aware format for fewer scale surprises.
- Future-proof your models for tools that expect 3MF containers.
- Better alignment with multi-part and multi-process workflows.
Technical Notes & Limitations
- No new colors or materials from STL: STL has no color/material data. Your 3MF will start without appearance layers unless you add them later in CAD/slicer.
- Units: STL is unitless. Set or confirm millimeters (or your target unit) after converting.
- Mesh quality: Non‑manifold or self‑intersecting meshes should be repaired before conversion to ensure best slicer behavior.
- Assemblies: A single STL becomes a single mesh object. Multi‑part organization must be rebuilt if starting from one STL.
How to Convert STL to 3MF
1) Select
Choose one or more .stl files in the upload box above.
2) Convert
We package the triangle mesh into a valid 3MF container locally in your browser.
3) Set Units
Open the 3MF in your slicer and select the intended unit (e.g., mm).
4) Save
Archive and share a single portable .3mf project file.
Best Practices
- Repair meshes with tools like Netfabb or Meshmixer.
- Remove duplicate vertices and degenerate faces.
- Ensure normals are consistently oriented outward.
- Verify scale after import; set millimeters if unsure.
- Split multi‑body STLs in CAD before packaging to 3MF if you need separate parts.
- Document print notes in the 3MF for teammates.