Free image to STL – no sign-up
3MF to STL Converter
Open a 3MF file, preview the model and download it as a binary STL for any slicer. Your file stays on your device.
Convert to
Drop a 3D file to convert it.
STL, OBJ, GLB, GLTF, 3MF or PLY · stays on your device
Free, without a catch
Convert as many pictures as you like. No account, no watermark, no daily limit.
Your picture stays yours
The model is built on your phone or computer. The image is never uploaded.
Ready for your slicer
A closed, watertight STL that opens in Cura, PrusaSlicer, Bambu Studio and other slicers.
How it works
- 1
Drop your 3MF file
Drag it onto the page or tap to pick it. The model appears in the 3D preview with its size and triangle count.
- 2
Check units and orientation
3MF files are usually in millimeters and Z-up, so the defaults are right for most downloads. Change the units selector if the size looks off.
- 3
Choose STL and download
Keep STL selected as the output and download. Open the file in your slicer and slice as usual.
Why convert 3MF to STL?
3MF is a modern 3D printing format: a zipped package that can hold several objects, colors, materials and slicer settings. STL is much simpler. It stores only a triangle mesh, which is why almost every slicer, CAD tool and online service can read it. Convert 3MF to STL when a program refuses your file, when you want a single clean mesh to repair or scale in another tool, or when you want to share just the shape without any project settings.
3MF files from Bambu Studio, OrcaSlicer and MakerWorld
Project files saved from Bambu Studio or OrcaSlicer and many 3MF downloads from MakerWorld contain every object on the build plate, sometimes with multiple colors or parts. This converter merges all objects in the file into one model, so a plate with three parts becomes a single STL with three separate shells. Colors and materials are dropped, because STL has no way to store them.
If you only need one part from a multi-part project, export that part from your slicer on its own first, or separate the shells later in your slicer's split tool. Slicer settings such as infill and supports are not part of the STL either, so you will set them again after importing.
What you lose, and what you keep
You keep the geometry: the exact triangles of the model, at the same position and scale. You lose colors, textures, per-object settings, modifiers and any embedded thumbnail. Make sure the preview shows the whole shape and that the size matches what you expect before you download.
A binary STL is written, which is much smaller than an ASCII STL and is read by every current slicer. The file is created in your browser; nothing is sent to a server, and the tool is free with no limit on conversions.
Common problems
If the model looks tiny or huge, change the units selector: a 3MF saved in inches or meters will look wrong if read as millimeters. If parts overlap or the slicer reports non-manifold edges, the original project probably contained overlapping objects. Merging keeps them as they are, so repair the mesh in your slicer or a mesh repair tool. Very large 3MF files depend on your device's memory, so on a phone try a smaller file or a desktop browser.
Frequently asked questions
Is this 3MF to STL converter free?
Yes. It is free and unlimited, with no sign-up and no watermark.
Is my 3MF file uploaded?
No. The file is read and converted inside your browser and never leaves your device.
What happens to a 3MF with several objects?
All objects in the file are merged into one model and exported as a single STL. Each object keeps its position, so a full build plate stays laid out as it was.
Are colors kept in the STL?
No. STL has no color or material data, so colors from the 3MF are dropped. Only the shape is kept.
Can I convert STL back to 3MF?
This tool exports STL, OBJ, GLB and PLY. For a 3MF, import the STL into your slicer and save the project from there.
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