STEP (STP) to STL converter, free online

Convert a STEP or STP file to STL for 3D printing, online. It's free, there's no account to make, and the file is never uploaded.

How to do it

Drop the STEP or STP file on the converter above, or choose it. The STL downloads with every part in it.

To print one part of an assembly, open the file in the studio, hide the other parts, and choose Export STL there. Hidden parts are left out.

What's in the STL

• Every part, where the assembly places it, in one file.
• Binary STL, in millimetres, which is what slicers expect.
• Triangles within 0.05 mm of the true surface, and closer on small parts: the kernel meshes each part to a tenth of a percent of its size.
• Every triangle facing outward, with its normal worked out from its corners.

STL holds triangles and nothing else, so the part names, colours and the assembly's structure aren't in it. The STEP file stays the exact model; the STL is a close copy made of flat facets.

STEP to STL, not the other way

The studio opens STEP (.step, .stp), IGES (.iges, .igs) and BREP (.brep) files. It can't open an STL, because a mesh has no exact edges to draw.

Your file stays on your computer

The studio reads the STEP file and makes the STL in your browser, with the Open CASCADE geometry kernel compiled to WebAssembly. Neither is sent to us or to anyone else. Security and your files says exactly what is and isn't sent.

Free, with no account

STL export is on the free plan. The free plan keeps one file in your browser at a time. The same file can also become an exact hidden-line drawing, exported as SVG, DXF, PDF or PNG.