Question 1

Is my file uploaded when I convert 3MF to STL?

Accepted Answer

No. Everything runs in your browser with three.js: the 3MF is read from your disk, unzipped and converted in memory, then saved to your downloads. Nothing reaches a server, so it's fine for client parts and unreleased designs.

Question 2

Does 3MF to STL work with Bambu Studio and PrusaSlicer files?

Accepted Answer

Yes, their mesh geometry. We tested project files saved by Bambu Studio and PrusaSlicer. Settings and paint colours are dropped, and modifier shapes stored in a project can appear as extra geometry, so check the preview.

Question 3

Does 3MF to STL keep the colours?

Accepted Answer

No. STL stores triangles only, with no colour, material or texture. Paint, filament assignments and textures stay in your 3MF, so keep the original for multi-colour prints and reopen it in your slicer whenever you need them.

Question 4

What happens to multiple objects and plates?

Accepted Answer

Every object in the 3MF build is merged into one STL, at the position saved in the file. For multi-plate projects only the mesh geometry is converted; to get one plate, export that plate from your slicer first.

Question 5

Can I convert STL to 3MF here?

Accepted Answer

No. This tool reads 3MF but can't write it, so 3MF to STL only goes one way here; the outputs are STL, OBJ, PLY and GLB. To make a 3MF, import the STL into your slicer and save the project.

Question 6

How large can the 3MF file be?

Accepted Answer

Up to 200 MB per file, and up to 10 files per batch. Because 3MF to STL runs in your device's memory, very large meshes depend on the RAM available; if a file fails, close other tabs and try again.

Question 7

Is STL or 3MF better for 3D printing?

Accepted Answer

3MF is richer: one package holds units, colours, several objects and print settings. STL is simpler and opens almost everywhere. Use 3MF inside your slicer, and convert 3MF to STL when another app needs a plain mesh. Our 3MF vs STL guide goes deeper.

Question 8

Is this 3MF to STL converter free? Do I need an account?

Accepted Answer

It's free and works without signing in. Everything runs in this browser tab, so there is no upload, no queue and no copy on a server. You only need a Kairo3D account to generate new 3D models from a photo or text.

Question 9

Can I export STL from Bambu Studio or PrusaSlicer instead?

Accepted Answer

Yes, if the slicer is installed: open the project and save STL from its File → Export menu. This 3MF to STL converter is for when it isn't, such as on a work laptop or a Chromebook, or when you just want to check a downloaded project first.

Question 10

Will the STL open in Cura, OrcaSlicer or Tinkercad?

Accepted Answer

Yes. The download is a standard binary STL with its numbers in millimetres, which Cura, OrcaSlicer, PrusaSlicer, Bambu Studio, Tinkercad and Blender all import. Every object arrives in one mesh at its 3MF position; use Split to objects in PrusaSlicer, Bambu Studio or OrcaSlicer to arrange parts separately.

3MF to STL Converter, Free and Private

The converter in plain numbers

How to convert 3MF to STL

Drop the .3mf

Check the preview

Download the STL

What a 3MF to STL conversion keeps

Printable models to spin

Why use this 3MF to STL converter

Private by design

Multi-object projects

Units handled

Same orientation

Batch 3MF to STL

3MF to OBJ too

3MF to STL FAQ

More ways to work with your 3D files

STL viewer

3MF vs STL guide

OBJ to STL converter

Image to STL

No 3D model yet?

What a 3MF to STL conversion keeps	3MF	STL
Triangle mesh	Yes	Yes
Several objects	Yes	Merged
Colours and materials	Yes	No
Print settings, plates	Yes	No
Units	mm, inch…	mm