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.3mf3MF→.stlSTLlossless

Convert 3MF to STL

Convert 3MF to STL in your browser. The conversion runs on this page and the file never leaves your computer.

Drop your .3mf file

up to 250 MB · .3mf

Free, and it opens in this tab. Nothing is uploaded, and there's no account to make.

Runs locally · nothing uploaded

Before you convert: what this keeps and what it destroys

Preserved

  • The geometry, triangle for triangle
  • Overall dimensions and proportions
  • Watertightness, where the input is watertight

Destroyed

  • A recorded unit: STL stores none
  • Colour
  • The separation between parts, merged into one body

↺ the reverse: STL → 3MF · about .3mf · about .stl · just view it instead

Why people convert 3MF to STL

You do this when something at the other end only accepts STL: an older print service's upload form, a legacy slicer, or firmware-driven tooling.

What happens to a 3MF slicer project?

STL contains a triangle surface. It has no place for printer profiles, support settings, colour assignments or the component structure of a 3MF project. Exporting the shape does not transfer the print setup.

Keep the original 3MF project before converting. In the receiving slicer, check the part size and orientation, then configure the print settings there. Review the layer preview before sending the job to the printer.

Separate pieces can still exist as disconnected surfaces in an STL, but their component names and hierarchy do not travel with them. Some applications can split those surfaces after import; do not rely on that as a replacement for the original project. If you only need to inspect the model, use the 3MF viewer.

The conversion runs in your browser. Your file stays on your computer and is not uploaded.

Going the other way

Convert STL back to 3MF. The reverse conversion also works with mesh geometry. It does not reconstruct exact CAD surfaces. Material data and part structure lost in either direction cannot be restored by converting back. Keep the original file for later edits.

How we know this conversion works

This pair was checked against 13 files from the test corpus on 2026-09-04. Each run parses its own output back in and compares the bounding box, the triangle count and, for closed solids, the volume against the input.

A pair that fails those checks doesn't get a page. That's why this site lists 120 conversions and not the several hundred a format-times-format grid would suggest.