Convert STL to STEP Online
Convert an STL file to a STEP file directly in your browser — a free STL to STEP converter with no upload and no install. Preview the geometry, then download a spec-valid, faceted STEP file for your CAD software.
STEP is a CAD interchange format; this converter outputs a faceted shell — your mesh's triangles, each as a flat face — the honest result of converting a triangle mesh, not a smooth parametric solid.
Drop your STL file here
Supported format: .STL
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Frequently Asked Questions
What is a STEP file?
STEP (ISO 10303) is a standard CAD interchange format, most often used to represent precise, parametric solid models between CAD applications.
How do I convert an STL file to STEP?
Drop your .stl file into the STL to STEP converter above, preview the geometry, then click Convert to STEP and download the .step file — all in your browser, with no upload of your model to a server.
Can you convert STL to STEP?
Yes, with an important caveat: this tool outputs a spec-valid, faceted STEP file (your mesh's triangles as flat faces), not a smooth parametric CAD solid — see the next question for why that's the honest answer rather than a limitation of this converter specifically.
Does this produce a real parametric CAD solid?
No. STL contains only triangle mesh data with no surface or curve information, so there's no way to reconstruct a smooth parametric solid from it. This tool outputs a spec-valid STEP file using a faceted representation — your mesh's triangles, each as a flat face — not a smooth CAD solid.
Will the STEP file open in my CAD software?
It should open in most STEP-compatible CAD tools as a faceted shell. Very large models can produce very large STEP files, since STEP's faceted representation is verbose per triangle.
Is my STL file uploaded to a server?
No. The conversion happens entirely in your browser. Your file is never sent to our servers.
Why is my STEP conversion slow?
Faceted STEP files grow roughly 24x the triangle count in entities. Models with tens of thousands of triangles can take noticeably longer to convert and produce much larger files.