Free Online Converter

Convert STL to 3MF

Drop a .stl file, get a .3mf back in seconds. Runs entirely in your browser — no upload, no signup, no watermark.

Drop your 3D file here, or browse

Supports .STL · Max 200MB

🔒 Files never leave your browser. 100% local.

No .stl handy?

How to convert STL to 3MF

Drag your .stl file into the box above (or click to browse).
Preview the model in the viewer — drag to rotate, scroll to zoom.
Click Convert & Download .3mf. The .3mf file lands in your downloads folder.

Conversion runs in your browser via three.js. Your file never leaves your device — there's no upload, no server, and nothing is stored.