Layerpaint Open the painter
Free · No upload · Runs in your browser

Convert 3MF to STL, free and online

Drag in a .3mf file, see it in 3D, and download a clean STL. The whole thing runs on your device — your model is never uploaded. Works the other way too: drop an STL to get a 3MF.

Drop a 3MF file here

or choose a file — converts to STL instantly. You can also drop an STL to convert it to 3MF.

.3MF · .STL · max ~200 MB
drag to rotate · scroll to zoom
File—
Triangles—
Vertices—
Size—

Loading model…

Reading file…

Want it in colour? STL and plain 3MF carry geometry only. Paint your model per-region in Layerpaint and export a Standard 3MF your slicer prints in multiple filaments.

Open the painter →

🔒 Files are processed locally in your browser and never uploaded.

3MF to STL, the simple way

3MF is the format Bambu Studio, OrcaSlicer and PrusaSlicer save by default — it bundles the mesh together with print settings, supports and colour. STL is the older, universal format that every slicer, viewer and CAD tool reads. When a site, printer or piece of software only accepts STL, you need to convert, and this tool does it in one drag.

Everything happens in your browser. The .3mf archive is unzipped and parsed on your machine, the geometry is shown in the live 3D preview above, and the STL is written locally for download. No file ever leaves your device — handy for client work or anything you'd rather not upload to a random web service.

What gets kept — and what doesn't

STL stores triangles and nothing else. A 3MF can hold per-object colour, multi-material paint and print settings, and all of that is dropped when you export to STL — you keep the shape, you lose the colour. If colour is the point (multi-filament or AMS printing), don't flatten to STL: paint the model in Layerpaint and export a Standard 3MF that your slicer prints in real filament.

Converting STL back to 3MF

Drop an STL instead and the tool produces a geometry-only 3MF that opens cleanly in Bambu Studio, OrcaSlicer and PrusaSlicer. It's a good first step before adding colour: convert to 3MF, then open it in the painter to lay down per-region colours.

Questions

Is the conversion done in my browser?
Yes. The file is read and converted entirely on your device in JavaScript — it's never uploaded to a server. Large or confidential models stay with you.
Does converting 3MF to STL keep the colours?
No. STL has no concept of colour; it's geometry only. Any per-object colour or multi-material paint in the 3MF is dropped. To keep or add colour for multi-filament printing, paint in Layerpaint and export a Standard 3MF.
Can it convert STL to 3MF as well?
Yes — drop an STL and you'll get a minimal, geometry-only 3MF that opens in Bambu Studio, OrcaSlicer and PrusaSlicer.
Will the STL open in my slicer?
Yes. The output is a standard binary STL that loads in Bambu Studio, OrcaSlicer, PrusaSlicer, Cura and any STL viewer. Units are treated as millimetres to match the 3MF source.
What about multi-plate 3MF files?
If a 3MF holds several objects or plates, they're merged into one mesh in the STL. Need them separate, or need colour preserved? Open the file in the Layerpaint painter instead.