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Convert 3MF to STL in Your Browser

3MF is the project format of modern slicers and model sites such as MakerWorld and Printables. Some tools, older slicers and CAD programs still only accept STL. This page reads the 3MF package on your device, applies each object's position and units, and gives you STL files.

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How to use it

  1. 1

    Add your .3mf

    Drop the file onto the box or click to choose it. Slicer projects with several plates and objects are supported.

  2. 2

    Check what was found

    All objects on the build plate are shown in their arranged positions, with the total size in millimetres.

  3. 3

    Merge or split

    Download one STL with everything, or tick "one STL per object" to get a ZIP with a separate STL for each part.

  4. 4

    Load into your tool

    Each STL keeps the same placement, so split parts line up again when you load them together.

What to know before you convert

  • STL is geometry only. Filament colours, painted areas, plate layout, supports and all print settings in the 3MF are not carried over.
  • Sizes are converted to millimetres from the unit the 3MF declares (micron, millimetre, centimetre, inch, foot or metre).
  • Every object placed on the build plate is included, in the position it was arranged in. Modifier meshes and other non-printing helper objects are skipped.
  • Encrypted 3MF files and the beam-lattice and slice extensions are not supported. Those are rare outside industrial printers.
  • The mesh is not repaired. If the 3MF had open edges or overlapping parts, the STL will too; the info panel shows whether it is watertight.

3MF or STL: Which Should You Keep?

3MF is a ZIP package that stores the mesh together with its units, colours, several objects and, from slicers, the plate layout and print settings. STL stores triangles only. For printing again in Bambu Studio, OrcaSlicer or PrusaSlicer, keep the 3MF: it holds everything you set up.

Use STL when a program does not accept 3MF: older slicers, many CAD and mesh-editing tools, some print services and model sites, and laser or CNC software. Converting a copy keeps your 3MF intact.

Exporting STL From Your Slicer Instead

If the project is already open in a slicer, it can export STL itself: in Bambu Studio and OrcaSlicer look under File > Export, and in PrusaSlicer under File > Export > Export Plate as STL. This page is quicker when you only have the file, for example a 3MF downloaded from MakerWorld or Printables, or when you are on a computer without a slicer.

Want to see the 3MF first? Open it in the 3MF Viewer. Need to go the other way? Use STL to 3MF. For Blender or other 3D apps, 3MF to OBJ keeps the objects separate.

Don't have a model?

Create one with AI from a photo, a sentence or a sketch. The generators use credits; this converter is free and stays in your browser.

Image to 3D →Turn one photo into a textured 3D model.Text to 3D →Describe an object and get a GLB.Sketch to STL →Draw it, get a printable model.

Frequently Asked Questions

STL stores only triangles. Multi-colour information in a 3MF, such as filament assignments or painted faces, has nowhere to go. Keep the 3MF for colour printing and use the STL for tools that need plain geometry.
Yes. Their projects store each object in its own file inside the 3MF package and point to it from the build plate. The converter follows those references, so every object comes out with the right shape and position.
Yes. When the 3MF has more than one object, tick "One STL per object". You get a ZIP with one STL per object, each named after the object and placed where it sat on the plate.
Yes. A 3MF declares its unit, and the converter turns it into millimetres, which is what slicers expect from an STL. A model saved in inches is multiplied by 25.4.
A 3MF is a ZIP-compressed archive that shares corner points between triangles. A binary STL stores three full corners for every triangle and is not compressed, so it is often several times larger.
Drop the .3mf above and download. Bambu Studio and OrcaSlicer projects are read the same way as any other 3MF: every object on every plate comes out in the right size and position. Tick one STL per object if you want the parts separately.
Yes, with STL to 3MF. It turns an STL into a 3MF with millimetre units, ready for Bambu Studio, OrcaSlicer, PrusaSlicer or Cura. Colours and print settings are not added; you set those in the slicer.
No. The page reads the file and converts it inside your browser with the open-source three.js library. Nothing is sent to our servers, there is no account, and no credits are used. Closing the tab discards everything.