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3DPrintMates

STL to 3MF converter

Package an STL into a compact 3MF with explicit millimeter units. Useful for sharing models, archiving and fixing files exported in the wrong unit.

Convert.stl→ .3mfRuns locally

Drop a file here or

.stl · processed on your device, never uploaded

How to use the STL to 3MF

  1. 1Choose an .stl file (binary or ASCII).
  2. 2Confirm the source units - most STLs are millimeters.
  3. 3Check the size and preview.
  4. 4Download the .3mf.

How much smaller is 3MF?

A binary STL repeats every vertex for each triangle that touches it and stores a normal per triangle - 50 bytes per facet. 3MF stores each vertex once and zips the result, so the same mesh is often several times smaller. Learn more in STL vs 3MF.

Frequently asked questions

Why convert STL to 3MF?

3MF records the unit explicitly, shares vertices between triangles and is compressed, so files are usually smaller and always open at the intended size.

Will the 3MF include print settings?

No. The output is a clean 3MF containing the mesh in millimeters. Add print settings, colors and plates in your slicer.

Which slicers open the 3MF?

Standard 3MF is supported by Bambu Studio, PrusaSlicer, OrcaSlicer, Cura and most CAD tools.

What if my STL was in inches?

Choose inches as the source unit before downloading. The 3MF is written in millimeters at the correct size.