Convert STL files to 3MF online free in your browser. Preserve real-world units, eliminate scale errors, edit mesh geometry, and export 3MF, STL, OBJ, or GLB for any 3D printer slicer.
Drag your .stl file into OwlCAD in your browser, verify its dimensions, and click Export to save it as a 3MF file. No software installation, conversion credits, or account creation required.
Upgrade legacy STL files to the modern 3MF format with exact scale and smaller file sizes.
STL files store unitless vertex coordinates, which is where scaling bugs come from. 3MF embeds explicit millimetres so models load at the right size in every slicer.
3MF is a ZIP archive of compact XML, so a converted file is typically a fraction of the size of the equivalent ASCII STL.
Inspect wall thickness, hollow solid volumes, repair non-manifold triangles, and combine parts before generating your output 3MF.
Drop your STL onto the build plate, refine your model, and export print-ready 3MF free in your browser.
Drag your .stl file into OwlCAD in your browser, verify its dimensions, and click Export to save it as a 3MF file. No software installation, conversion credits, or account creation required.
3MF packs the mesh alongside exact real-world units, materials, colour data, and print metadata into a smaller, compressed archive. Unlike unitless STL files that can load at the wrong scale, 3MF removes unit ambiguity in slicers like PrusaSlicer, Bambu Studio, and Cura.
Yes. Once imported into OwlCAD, you can scale to exact millimetres, combine with parametric shapes using booleans, hollow the part for resin printing, and fix non-watertight mesh errors before exporting.
Yes. Importing, editing, repairing, and exporting STL, 3MF, OBJ, GLB, and STEP files in OwlCAD is 100% free. AI generation is the optional Pro upgrade.