Browser-based 3D file tools
Convert STL to 3MF online
Package an ASCII or binary STL mesh in a 3MF file with explicit millimeter units. Choose the units used by your source STL before converting. Your file stays on your device.
STL → 3MF
Free · On your device · No sign-up
Up to 25 MB and 1 million mesh triangles. Your file is processed locally, not uploaded.
STL has no unit metadata. Match the unit used when your file was exported.
Need to create a model first?
Start from a reference image with Magic3D. AI generation uses credits; this file converter is free.
Create a 3D model from an imageHow to convert STL to 3MF
Step 1
Choose your STL file
Select an ASCII or binary STL up to 25 MB, or try the sample.
Step 2
Confirm the source units
STL does not store units. Choose millimeters or inches to match the source model.
Step 3
Download your 3MF
Open the mesh-based 3MF in your slicer and check the dimensions before adding print settings.
What this conversion preserves
This creates a mesh-based 3MF file, not a configured slicer project. STL has no standard color or material data, so conversion cannot recover colors, textures, supports, or printer settings. It does not repair holes or automatically prepare a model for printing.
Frequently asked questions
Is STL to 3MF conversion free?
Yes. This file converter works locally in your browser with no account, subscription, or credit charge. AI generation and other paid processing tools have separate costs.
Does converting STL to 3MF make a model multicolor?
No. Changing the file container does not add missing color or material information. You can assign colors and print settings later in a compatible slicer.
How do I choose the correct units?
Choose the unit used when the STL was exported. Millimeters are common for printing; choose inches only if the original coordinates use inches. The resulting 3MF declares millimeters. Always check the displayed dimensions.
Will the result include my slicer settings?
No. The output contains the model mesh and its units. Import it into your slicer to choose a printer, orientation, supports, and print settings. Keep the original file as a backup.