Open the STEP / STP to STL Converter
Convert STEP / STP and IGES / IGS CAD files to STL, 3MF, OBJ, PLY or GLB for 3D printing. Uses the real OpenCascade CAD kernel inside your browser.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
A 10 × 10 × 10 mm STEP cube converts to a 12-triangle STL with exactly 10 × 10 × 10 mm size and 1.00 cm³ volume. A filleted bracket tessellated at Normal quality becomes a few thousand triangles; at Ultra it can reach hundreds of thousands, so only use Ultra when you really need it.Open the STEP / STP to STL Converter
Illustration. Open the tool for the real thing.
What is the STEP / STP to STL Converter?
STEP (.step / .stp) and IGES (.iges / .igs) files are the neutral formats CAD programs use to exchange true solid models — but 3D printers and slicers only understand triangle meshes such as STL or 3MF. Converting between them means tessellating the exact curved surfaces of the solid into triangles. This converter does exactly that with OpenCascade, the same open-source CAD kernel used by FreeCAD, running as WebAssembly inside your browser tab.
Because the conversion happens locally, your design never leaves your computer — useful for client work, coursework under an academic-integrity policy, or any model you do not want on someone else's server. Pick the mesh quality (draft to ultra), the output format and the output unit, then download. A live 3D preview lets you check the result before it reaches your slicer.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Reads genuine STEP AP203/AP214/AP242 and IGES B-rep geometry — not a renamed file.
One upload, any mesh output. Binary or ASCII STL, 3MF for modern slicers.
Draft, Normal, Fine and Ultra tessellation so curved parts print smooth without 500 MB files.
Convert several files at once and download a ZIP. Nothing is uploaded.
AZRS tools are free to open and use.
It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
Students and hobbyists with Onshape/Fusion free accounts
Get from a STEP download to a printable STL without installing anything.
Try it freeMakers sharing models
Turn CAD downloads from manufacturers (STEP) into print-ready meshes.
Try it freeEngineers handling confidential parts
Convert locally so the geometry never touches a third-party server.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This 3d tool | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
| Where it runs | In your browser tab | On your computer |
Questions people ask
Is my STEP file uploaded to a server?
No. The CAD engine is downloaded to your browser (about 7 MB, cached afterwards) and the file is read locally.
Which STEP versions are supported?
STEP AP203, AP214 and AP242 solid models, plus IGES and BREP, via OpenCascade.
Why is the first conversion slower?
The WebAssembly CAD engine has to be downloaded once; later conversions start immediately.
Can it convert STL back to STEP?
Yes — see the STL to STEP converter, which builds a real planar-faced B-rep solid.
What mesh quality should I choose?
Normal for most FDM prints, Fine for smooth cylinders and resin printing, Draft for quick previews.
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Try the STEP / STP to STL Converter now
Convert STEP, STP & IGES CAD files to STL, OBJ, 3MF — free, in your browser. Free to use.
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