Is this STEP to STL converter really free?

Yes — unlimited conversions, no account, no watermark, no file-size tricks.

Which files can I convert?

.stp / .step (STEP AP203/AP214/AP242) and .iges / .igs (IGES 5.x).

What STL variant is produced?

ASCII STL with millimeter-preserving tessellation (0.1 mm linear deflection), compatible with every major slicer.

Why does the first conversion take a while?

The geometry kernel is about 50 MB of WebAssembly and is downloaded once, on demand. Later conversions start instantly (it's cached by your browser).

Can I convert STP to OBJ instead?

Yes — use our STP to OBJ converter, which uses the same engine.

STEP to STL Converter — Free Online, No Sign-up

How the STEP to STL conversion works

Drop your file above — a .stp, .step, .iges or .igs file.
The page loads the OpenCASCADE geometry kernel (compiled to WebAssembly) only when you need it, so the rest of the site stays fast.
Your CAD model is tessellated into triangles and written as an STL file, ready for 3D printing or slicing.
Preview the result in 3D, then download the .stl.

Why convert STEP to STL?

STEP (ISO 10303) is the standard exchange format for CAD software — SolidWorks, Fusion 360, FreeCAD, CATIA and others all export it. But 3D printers and slicers (Cura, PrusaSlicer, Bambu Studio) speak STL, a simple triangle-mesh format. This tool bridges the gap: it reads the precise B-Rep geometry from your STEP file and tessellates it into a printable STL mesh, all locally in your browser.

Private by design

Most online converters upload your CAD files to a server. This one doesn't. Both the file parsing and the mesh generation happen in WebAssembly code running on your own machine — nothing is transmitted anywhere. You can even disconnect from the internet after the page loads (except for the one-time engine download).

FAQ

Is this STEP to STL converter really free?: Yes — unlimited conversions, no account, no watermark, no file-size tricks.
Which files can I convert?: .stp / .step (STEP AP203/AP214/AP242) and .iges / .igs (IGES 5.x).
What STL variant is produced?: ASCII STL with millimeter-preserving tessellation (0.1 mm linear deflection), compatible with every major slicer.
Why does the first conversion take a while?: The geometry kernel is about 50 MB of WebAssembly and is downloaded once, on demand. Later conversions start instantly (it's cached by your browser).
Can I convert STP to OBJ instead?: Yes — use our STP to OBJ converter, which uses the same engine.