STEP to STL Converter
Convert STEP CAD parts into STL for 3D printing. STEP holds exact boundary-representation solids, which slicers can’t read — so we tessellate those surfaces into the triangle mesh STL expects, at a resolution you control. It all happens locally in your browser; your part files are never uploaded.
How conversion works
- Drop your STEP partDrag a .step or .stp part onto the converter — read locally, never uploaded.
- Set mesh resolutionBalance surface smoothness against file size with the mesh-detail control, and preview in 3D.
- Download the STLGrab the binary STL and load it straight into your slicer.
What you can do
- Reads .step / .stp solids (AP203/214/242) and meshes them for slicing.
- Adjustable deflection controls print resolution — coarse for drafts, fine for smooth curved surfaces.
- Writes compact binary STL that loads straight into Cura, PrusaSlicer, Bambu Studio and every common slicer.
- Consistently outward-oriented triangles, so slicers see a clean, solid part.
- Studio-lit 3D preview of the mesh before you commit to the download.
- Entirely in-browser and free — CAD data stays on your machine, no account required.
Important limitations
- Tessellation is one-way and lossy: the exact CAD surfaces become a fixed triangle mesh you can’t convert back to STEP.
- Surface smoothness is set by the deflection tolerance — over-coarse settings show facets on curved walls.
- STL is geometry-only: colors, materials, units and assembly metadata are dropped.
- STL has no units; most STEP files are in millimetres, so confirm scale in your slicer.
- Watertightness follows the source solid — a clean STEP solid meshes to a printable mesh, but a malformed input may need a pass through an STL repair tool.
Questions, answered
Can I 3D print a STEP file directly?
Not usually — slicers need a mesh. Converting STEP to STL here gives your slicer the triangle mesh it expects.
What mesh resolution should I use?
For most prints the default is fine. Choose Fine for smooth curved surfaces (at the cost of a bigger file); choose Draft for fast previews.
Is the output watertight and print-ready?
A clean STEP solid tessellates into a solid, consistently-oriented STL. If your source geometry has issues, run the result through our STL repair tool.
Are my files uploaded?
No. STEP parsing and STL export both run in your browser via WebAssembly. Nothing leaves your device.
Binary or ASCII STL?
We write compact binary STL for a smaller download; every mainstream slicer reads it.