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Online STEP to STL Converter

Drop a STEP or STP file, check the model in 3D, choose the mesh quality and download the STL ready for your slicer. Everything runs in your browser: nothing is uploaded.

Drop your STEP or STP file hereor click to choose a file. It never leaves your device.

Batch conversionPremium

Convert many STEP files to STL at once and download them together in a ZIP. Ideal for workshops and projects with lots of parts.

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How to convert STEP to STL

  1. 1

    Drag your STEP or STP file onto the box above, or click it to choose a file.

  2. 2

    Check the 3D preview and the dimensions to make sure it is the right part.

  3. 3

    Choose the mesh quality: Normal for most parts, Fine or Ultra for smooth curves.

  4. 4

    Click “Download STL”. For assemblies you can also download one STL per part in a ZIP file.

Why convert STEP to STL?

STEP is the format CAD programs use to exchange exact geometry. 3D printing slicers such as Cura, PrusaSlicer, Bambu Studio or OrcaSlicer work with STL instead: a mesh of triangles.

Converting turns the exact surfaces into triangles. The more triangles, the smoother the curves look on the print, and the larger the file.

Choosing the right quality

Normal is enough for flat, boxy parts and for most prints. Fine smooths holes, fillets and cylinders. Ultra is for large or very curved parts where facets would show.

The estimated file size is shown on the download button, so you can compare before downloading.

Real units, ready to print

STEP files store their units, so the STL is always exported in millimeters, the unit slicers expect. A part designed in inches arrives at its real size, with no scaling needed.

The model keeps its orientation, with Z pointing up as in your CAD program.

Frequently asked questions

Is the STEP to STL converter free?

Yes. You can convert files for free, without an account and without watermarks.

Are my files uploaded to a server?

No. The conversion runs entirely in your browser with OpenCascade, the same open-source CAD engine used by FreeCAD. Your file never leaves your device.

What units does the STL use?

Millimeters. STL has no units, so slicers assume millimeters; the converter takes the units stored in the STEP file into account so the part prints at its real size.

Can I convert an assembly?

Yes. You can download the whole assembly as a single STL, or each part as a separate STL inside a ZIP file.

Is the STL binary or ASCII?

Binary, the most compact and widely supported variant of STL.

Can I convert STL back to STEP?

Not with this tool. An STL only stores triangles, so turning it back into exact CAD surfaces requires reverse-engineering software.