Convert STEP to STL
Online

Drop the file into the box above and download the mesh. Nothing to install and no signup. The converter reads the STEP solid with FreeCAD's OpenCASCADE kernel, tessellates every surface into triangles, and writes a binary STL your slicer can open. A .step file to STL conversion is one upload and one download.

They are the same format with two spellings of the extension. Both are ISO 10303, and the three-letter .stp exists mostly because older Windows tools preferred three-character extensions. Upload either one: a .stp file is read exactly like a .step file, so an stp to stl job and a step to stl job are the same conversion.

Yes. It runs in the browser, costs nothing, and needs no account. Free use covers files up to 25MB and 5 conversions a day. Uploads are deleted within 24 hours.

STEP is the standard format for sharing CAD geometry between engineers, but 3D printers don't understand it. Slicing software like PrusaSlicer, Cura, and Bambu Studio requires triangle mesh input. Converting STEP to STL is the standard step before printing a part designed in SolidWorks, Fusion 360, or FreeCAD.

Deflection controls how closely the triangles approximate the original curved surfaces. A smaller deflection value produces more triangles and a smoother mesh, at the cost of a larger file and longer tessellation time. A larger value is coarser but faster. For 3D printing, a deflection of 0.01 to 0.05mm is usually enough. For visualization, 0.1 to 0.5mm is fine.

Yes. The deflection parameter controls mesh density. Lower values give finer meshes that better capture curved surfaces. Higher values produce coarser meshes with fewer triangles. For most functional 3D printed parts, a deflection of 0.05 is a good default, fine enough to print cleanly without creating unnecessarily large files.

If the original STEP geometry is a closed solid, the resulting STL will be watertight. If the STEP file contains open surfaces or shells rather than a solid, the mesh will also be open. Most slicers handle this gracefully. If yours complains, our STL repair tool diagnoses the mesh and closes it, and there is a link to it below.

AP203 (configuration-controlled design), AP214 (automotive design) and AP242 (the current managed model-based 3D engineering schema). Most CAD software exports one of the three, and all of them are read by the underlying FreeCAD engine. The extension on disk, .step or .stp, makes no difference to which schema is inside.

That is the point of this page. Everything runs on our servers, so there is no FreeCAD, SolidWorks or Fusion 360 install involved and it works the same on a Chromebook or a phone as on a workstation. You need the file and a browser.

STL is universally supported: PrusaSlicer, Cura, Bambu Studio, Ultimaker, Meshmixer, Blender, Fusion 360 (mesh import), MeshLab, Netfabb, and thousands of other tools. If you need the model for rendering, OBJ or FBX may carry more material information.

Yes, though it is the harder direction. Tessellating a solid into triangles throws information away, so rebuilding CAD surfaces from a mesh means inferring what was there. Our STL to STEP converter attempts that reconstruction and tells you when it falls back to a faceted solid instead.