Convert a 3MF file to STL

Drop in a .3mf and get a plain .stl back. Unzipped and converted on your own machine, so the file never leaves your browser.

3MF → STL

Drop a 3MF file

or click to choose one. Your file never leaves your browser.

Runs locally · nothing uploaded3MF

Runs entirely in your browser. Your file is never uploaded, and there is no sign-up.

Why convert 3MF to STL

3MF is the better format, and that is exactly why people need this conversion. It is what Bambu Studio, PrusaSlicer and Cura hand you when you save a project, because it can hold colour, units, multiple objects and their arrangement on the plate. Plenty of other software never learned to read it.

Older slicers, print services that accept one upload format, mesh repair tools and a good deal of CAD software still expect an STL. Converting is how a project file becomes something those tools will open.

What survives, and what does not

STL stores triangles and nothing else, so the conversion is lossy by definition. Geometry and the position of each object come through unchanged. Colour, materials, object names and any per-object slicer settings do not, because the format has nowhere to put them.

One consequence worth knowing: a 3MF holding several objects becomes a single STL containing all of them, positioned as they were arranged. If you need them as separate files, split them in your slicer before exporting rather than after.

The units problem STL never solved

STL does not record a unit of measurement. A file is just numbers, and whether they mean millimetres or inches is an assumption the receiving program makes. That is the origin of the classic problem where a model arrives at 1/25th of its intended size, or 25 times too large. 3MF states its units explicitly, which is one of the reasons it exists.

This converter writes millimetres, which is what slicers assume. If a converted model opens at the wrong scale somewhere else, the unit assumption at the far end is the first thing to check.

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Frequently asked

Can a 3MF file be converted to STL?

Yes. A 3MF carries the same triangle mesh an STL does, wrapped in a zipped XML container alongside extra data like colour, units and per-object settings. Converting keeps the geometry and drops everything STL has no way to store.

Are 3MF and STL the same?

No. Both describe a mesh, but STL stores only triangles, while 3MF also records colour, materials, units, and how several objects are arranged on the plate. 3MF is the newer format and fixes STL's known gaps, including its lack of a defined unit of measurement.

How to convert 3MF to STL in Bambu Studio?

Open the 3MF, right-click the object in the plate view, and choose Export as STL. If the file holds several objects, export them one at a time to keep them as separate STLs, or export the plate to get one combined file.

How to convert 3MF to STL in Prusa Slicer?

Import the 3MF, then use File then Export then Export plate as STL. PrusaSlicer writes the objects as they sit on the plate, so move or split them first if you want them separated.

Is my file uploaded?

No. The 3MF is unzipped and parsed in your browser, and the STL is written locally. Nothing reaches our servers, and there is no account or sign-up.

What gets lost in the conversion?

Colour, materials, object names and any per-object slicer settings, because STL cannot represent them. The geometry and its arrangement survive intact, which is the part a printer actually needs.