STL Converter/convert/3mf-to-stl
Browser converter·no upload

3MF to STL, in your browser.

Drop a .3mf file, inspect it in real time, then download a clean .stl — binary or ASCII. Zero servers. Zero tracking.

viewer● live
drop a file to preview
Drop your .3mf file
or click to browse · local only
Output format

100% local · file never leaves your browser

// about

3MFSTL: what changes.

3MF is the modern, ZIP-based replacement for STL. It carries colors, units, components and metadata. Most slicers and printers still default to STL — geometry-only, universally supported.

Converting 3MF to STL drops color and material data (STL has no slot for it), but every vertex of every triangle is preserved exactly. Ideal for sending a model to a slicer that does not yet read 3MF.

Fully private

The file is parsed in WebAssembly + WebGL on your device. Nothing leaves.

Instant

No queue, no upload. Most files convert in well under a second.

Inspect before download

Orbit, pan and zoom the result in real time before you commit.

// faq

Frequently asked

Why does my slicer prefer STL?

Most firmware and many older slicers were written before 3MF existed. STL is bare geometry — easy to parse, impossible to misinterpret.

Is the conversion lossless?

For geometry, yes — vertex-for-vertex. Colors, materials and units are dropped because STL doesn't store them.

Binary or ASCII STL?

Binary for slicers (10× smaller). ASCII when you need to diff or hand-edit the mesh.

Is there a file size limit?

Only your browser's RAM. Files stay on your machine — nothing is ever uploaded.