Why would I need to convert 3MF to STL?

Use this converter when software or a service accepts STL mesh geometry. STL cannot preserve a full slicer project, colours, materials or print profiles.

Are multi-object plates handled correctly?

Core meshes, nested components and local production assembly references are flattened from the root build with their transforms. Unused resources and nonprintable build items are omitted. Unsupported required extensions, missing references and corrupt archives are refused.

No. The 3MF archive is unzipped and the STL written entirely by your browser. Nothing is transmitted, and that is also why there is no file-size cap.

What is lost in the conversion?

STL keeps triangles and their positions. It omits colours, materials, textures, metadata, object identities, assembly structure, slicer settings and print profiles. The complete summary lists observed property kinds and omitted package parts. Binary STL uses Float32 rounding; the mesh is not resampled, repaired or Boolean-unioned.

Binary STL. All coordinate values are written in millimetres, including unit and placement conversions. STL itself has no unit field, so choose millimetres when importing the result.

Is there a file size limit?

There is no file size cap. Available browser memory is the practical limit. Conversion stops after 30 seconds and can be canceled or replaced; a large model may need splitting in its source application.

How do I convert or recover my file?

Choose or drop a local .3mf, inspect the conversion summary, then download STL. If the browser refuses the download, the complete binary output is selectable as Base64 for local decoding. Choosing a replacement file, canceling or hiding the page clears earlier work. No file is stored on your device by this tool.

3MF to STL

Convert local 3MF build geometry to binary STL in your browser. Nested parts retain their placements, supported units are converted to millimetres, and mirrored parts keep their winding. No upload or file size cap; available memory limits conversion.

Drop a 3MF file anywhere

Local geometry conversion to binary STL in millimetres.

No upload · No account · No file size cap · Available memory limits conversion

Common questions

Why would I need to convert 3MF to STL?: Use this converter when software or a service accepts STL mesh geometry. STL cannot preserve a full slicer project, colours, materials or print profiles.
Are multi-object plates handled correctly?: Core meshes, nested components and local production assembly references are flattened from the root build with their transforms. Unused resources and nonprintable build items are omitted. Unsupported required extensions, missing references and corrupt archives are refused.
Is my file uploaded?: No. The 3MF archive is unzipped and the STL written entirely by your browser. Nothing is transmitted, and that is also why there is no file-size cap.
What is lost in the conversion?: STL keeps triangles and their positions. It omits colours, materials, textures, metadata, object identities, assembly structure, slicer settings and print profiles. The complete summary lists observed property kinds and omitted package parts. Binary STL uses Float32 rounding; the mesh is not resampled, repaired or Boolean-unioned.
Binary or ASCII STL?: Binary STL. All coordinate values are written in millimetres, including unit and placement conversions. STL itself has no unit field, so choose millimetres when importing the result.
Is there a file size limit?: There is no file size cap. Available browser memory is the practical limit. Conversion stops after 30 seconds and can be canceled or replaced; a large model may need splitting in its source application.
How do I convert or recover my file?: Choose or drop a local .3mf, inspect the conversion summary, then download STL. If the browser refuses the download, the complete binary output is selectable as Base64 for local decoding. Choosing a replacement file, canceling or hiding the page clears earlier work. No file is stored on your device by this tool.

Core mesh and local production assembly geometry is flattened in millimetres with transforms and mirrored winding applied. Binary STL rounds coordinates to Float32. No topology repair, Boolean union, watertightness check or printability certification is performed. Unsupported required extensions and invalid geometry are refused; STL omits nongeometry properties.