STL to 3MF Converter

Q: Why convert STL to 3MF?

A 3MF is a zipped XML package that records its unit, keeps several named objects and their positions in one file, and stores shared vertices instead of repeating them for every triangle, so files are usually smaller. An STL is one unnamed triangle list with no units.

Q: Are the objects kept separate?

Yes. Each STL (or each part you split off) is written as its own mesh object with its own build item, so Bambu Studio, PrusaSlicer, Cura and Orca list them separately and you can set them up individually.

Q: Why is my STL tiny or huge?

STL files store bare numbers without units, and slicers read them as millimeters. A model exported in inches shows up 25.4 times too small, and one exported in meters 1000 times too small. Use the Units buttons to convert it before printing or converting to 3MF.

Q: Does the 3MF include print settings or colors?

No. The converter writes a clean core-spec 3MF with geometry, object names and placement. Your slicer adds its own settings when you save a project from it.

Q: Are my files uploaded?

No. Files are read and processed by JavaScript in your browser tab, and downloads are generated locally. Nothing is sent to a server, so it also works with private or unreleased designs.

Turn one or more STL files into a single 3MF, with each file kept as a separate object in millimeters.

Open STL files to convert

Drop one or more STL files. Each becomes a separate object in one 3MF, in millimeters.

STL (binary or ASCII) and 3MF · files stay in your browser

How it works

Open one or more STL files. Each one becomes a separate object on the plate.
If a model is the wrong size, convert its units (inches, centimeters or meters to millimeters).
Optionally pick your printer and auto-arrange or drag the objects into place.
Click Download 3MF. Slicers open it with every object separate and in the positions you chose.

All five tools share one workbench, so files you open here stay loaded when you switch to STL & 3MF viewer, 3MF to STL, print bed arranger or mesh editor.

STL to 3MF Converter

How it works

FAQ

Why convert STL to 3MF?

Are the objects kept separate?

Why is my STL tiny or huge?

Does the 3MF include print settings or colors?

Are my files uploaded?

See also