Your files never leave your computer
Conversion runs inside this browser tab using OpenCascade compiled to WebAssembly. Nothing is uploaded, so it is safe for client and NDA work.
Free, no sign-up
Bulk STEP to STL converter
Drop in as many STEP or IGES files as you like. Everything converts in your browser, and nothing gets uploaded.
STEPIGEStoSTL
Runs on your device
Settings changed.
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Built for people who print
Pick the mesh quality
Draft, Standard or Fine. A tighter tolerance gives smoother curves and bigger files.
- Draft
- 0.2mm
- Standard
- 0.05mm
- Fine
- 0.01mm
Convert a whole folder
Drop dozens of files, or a whole folder, at once. They convert in parallel and download as one ZIP.
- .step
- .stp
- .iges
- .igs
Check it before you slice
Open any result in a 3D preview and orbit around it to make sure every part came through.
How to convert STEP to STL
STEP is the standard format for sharing CAD models. Slicers need a triangle mesh instead, which is what STL stores. This tool does the conversion on your own computer.
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Add your files
Drop STEP (.step, .stp) or IGES (.iges, .igs) files onto the converter, or click Choose files. You can also drop a whole folder.
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Pick a mesh quality
Standard works for most prints. Choose Fine for small parts with tight curves, or Draft for quick checks.
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Download your STL files
Save each STL on its own or everything as one ZIP, then open it in Cura, PrusaSlicer, Bambu Studio or OrcaSlicer.
STEP to STL questions
Are my files uploaded anywhere?
No. Your CAD files are read from your disk, converted in your browser's memory and saved straight back to your disk. Nothing is sent to a server.
Which file types can I convert?
STEP (.step, .stp) and IGES (.iges, .igs) go in, binary STL comes out. Binary STL opens in every common slicer, including Cura, PrusaSlicer, Bambu Studio and OrcaSlicer.
What units does the STL use?
STL files have no units. This tool exports in millimetres, which is what slicers assume, so parts load at the right size.
What do Draft, Standard and Fine mean?
They set how closely the triangles follow curved surfaces: within 0.2 mm, 0.05 mm or 0.01 mm. Standard suits most FDM and resin prints. Use Fine for small parts with tight curves.
What does "One STL per body" do?
By default an assembly becomes a single STL. Turn this on to get a separate STL for each body, grouped in a folder named after the source file.
Is STP the same as STEP?
Yes. .stp and .step are two file extensions for the same format (ISO 10303, often called STEP AP203, AP214 or AP242). Both work here, and there is a page just for STP to STL.
Can I convert STL back to STEP?
Not with this tool. STL only stores triangles, so the exact curves and features of the original CAD model are lost. Keep your STEP or IGES file as the master copy.
Is there a file size limit?
There is no fixed limit, but very large assemblies can run out of browser memory. If a file fails, try Draft quality or convert it on its own.
Is it really free?
Yes. No account, no watermark and no limit on the number of files.