Convert STL to STEP Free, Without Uploading Your Files
STL files are everywhere: 3D scans, 3D printing models, files from customers and downloads from online libraries. But most CAD packages (SolidWorks, Fusion, Inventor) work best with STEP. The CDI STL to STEP Converter bridges that gap. It's free, you don't need an account, and your file is never uploaded.
What it does
Drop in a binary or ASCII STL and pick the units it was modelled in. The converter writes a STEP file (AP214) that opens in your CAD software. If the mesh is watertight you get a solid body; if it has holes you get a surface body.
Dense meshes, like 3D scans, are automatically simplified to a face count your CAD package can handle (50,000 faces by default, and you can change it). You can preview the result in 3D before you download, and download a simplified STL as well.
Why it matters for businesses
- Keep customer files private: the conversion runs entirely in your browser, so nothing goes to a third-party upload site. That matters when you're handling a customer's design.
- Save time on quoting and fitment: get a scan or a customer's STL into your CAD package quickly to check fitment, design brackets around it or program CAM.
- No extra software: no paid converter or plugin just for the occasional STL.
Why it matters for DIY builders
- Use downloaded models in real CAD: bring a printable part or scanned component into Fusion or another CAD package to design around it.
- Big scans are handled: scans with millions of triangles are simplified so your computer and CAD software can cope.
- It's free: no sign-up and no watermark.
Good to know
A converted STL is a faceted solid made of many small flat faces. It's great for reference, fitment checks and CAM, but it isn't an editable parametric model with true cylinders and fillets. If you need that, our 3D scanning team can reverse-engineer the part into a clean, editable CAD model.
Try it now
Open the free STL to STEP Converter.
Just need to look at or measure a file? Try our free CAD File Viewer.