Convert STL to STEP Online
Turn an .stl mesh into a STEP solid that CAD tools and machine shops accept. Upload your file and view it free in the browser, then download it as STEP in Studio (1 credit). Runs in the browser, nothing to install.
Drag a .stl file onto the viewer above (or tap Upload) — it renders right here, free, nothing to install. To get the STEP, open it in Studio and hit Download — exporting the STEP costs 1 credit.
How to convert
- Upload your .stl file to the viewer above (drag and drop, or tap Upload). Files up to 75 MB are supported; very dense meshes are simplified automatically before conversion, so the finest detail may smooth slightly.
- View it free — the mesh is stitched into a closed solid and shown in 3D, so you can rotate, zoom, and confirm it is the right part before you spend anything.
- Download as STEP — open the model in Studio, click Download, and choose STEP. Exporting costs 1 credit.
What you get: flat faces clean, curves faceted
An STL is a blanket of triangles. A STEP stores exact faces and edges. Going from mesh to solid means rebuilding faces from triangles, and it is worth knowing exactly what that produces before you send the file to anyone:
- Flat faces come out clean. All the triangles lying on one flat face are merged into a single true planar face. A bracket, plate, spacer, or enclosure usually converts into a tidy solid with a handful of faces — the kind a CAD package or a machine shop can work with.
- Curves stay faceted. A hole or a rounded edge in an STL is already a ring of flat strips; the mesh never recorded that it was meant to be a perfect cylinder. Those surfaces carry over as many small flat faces. The STEP is still a valid closed solid, but a curve will not measure as an exact radius.
- Scans and sculpted shapes stay as triangles. Organic geometry has no flat faces to merge, so the STEP is essentially the mesh wrapped as a solid — fine for viewing and fit checks, not for further CAD edits.
Need exact curves? For a functional part, the cleanest STEP is a fresh one: describe the part in plain English, using the STL for its dimensions, and generate a true solid in Studio — real cylinders for holes, exact fillets, correct sizes. The full STL-to-STEP guide walks through when to convert and when to re-make.
Editing after conversion
When the mesh simplifies to a small number of faces, the result is editable: you can ask for a new hole, a pocket, or a changed dimension in plain English and re-export. Heavily curved or scanned meshes stay faceted, and operations like fillets and chamfers will not apply to them — Studio tells you which case you are in as soon as the file loads.
Common questions
How do I convert an STL file to STEP?
Upload the .stl to the viewer above — it renders free so you can check the part. Then open it in Studio, click Download, and choose STEP. The download costs one credit.
Is STL to STEP free?
Uploading and viewing are free and run in your browser. Downloading the converted STEP costs one credit — you only spend when you take the file.
Will the STEP have real curved surfaces?
Flat faces, yes; curves, no. Flat regions merge into true planar faces, while curved regions stay as small flat facets. If exact curves matter, generate a fresh solid instead of converting the mesh.
STL vs STEP — which do I need?
Send STEP to a machine shop or a CAD tool; send STL to a slicer. See STL vs STEP for the full comparison. Going the other way? Convert STEP to STL.
What if my file will not upload?
Most often it is over the 75 MB limit. Export a lower-resolution STL from your slicer or modeling tool and try again.
Convert your file
Upload your .stl above, check it in the free 3D view, then download it as STEP in Studio (1 credit). In the browser, nothing to install.