Which quality should I pick?

Normal suits most prints. Pick fine for large round parts, where flat facets would show at a 0.2 mm layer, and coarse when the file has to stay small. The setting changes the triangles, not the size: the part measures the same either way.

What is the difference between STEP and STL?

STEP stores exact surfaces, units and separate parts, for CAD programs and machining. STL stores triangles with no units, for slicers. Design and share in STEP, print from STL.

Does it convert .stp files and assemblies?

Yes. .stp and .step are the same format. An assembly converts with every solid in place, as one STL. To keep the parts apart, for printing them in different colours, convert STEP to 3MF instead.

Can I change the part before printing?

Not in the STL: once it is triangles, the sizes are gone. Change it in your CAD program and export the STEP again, or describe the part to Voloom, which builds a parametric model you can resize and download as STL.

Is the STEP to STL converter free?

Yes. You get 3 runs a month without an account. Sign in with your email, free, and there is no limit.

No. The file is read and converted in your browser. It never reaches our servers.

Will the STL keep colors and materials?

No. STL has no place for colors, and separate parts, so only the shape carries over.

What units is the STL in?

STEP: Explicit. Usually millimeters. STL: None in the file. Slicers read the numbers as millimeters. The converter does not guess. Use the scale option if the size looks wrong.

How do I open an STL file?

Bambu Studio, PrusaSlicer, Cura, OrcaSlicer, and Blender all open STL.

step to stl

Convert STEP to STL

Free STEP to STL converter. Runs in your browser, so the file never leaves your computer. Preview the model, then download the STL.

Drop STEP here, or choose a file

Stays in your browser. Nothing is uploaded.

Choose file

Good to know

The STEP is read by a real CAD kernel, OpenCascade, the one FreeCAD is built on, so every solid and curve comes in exactly as it was modelled, in millimetres whatever unit it was drawn in. Only then is it turned into triangles, and the quality decides how closely they follow the curves: fine for a smooth print, coarse for a small file. An assembly becomes one STL with every solid in place.

How it works

1Drop your STEP file in the box above. It is read in your browser.
2Check the preview. Pick a finer mesh quality for smoother curves, or coarser for a smaller file.
3Download the STL. It opens in Bambu Studio, PrusaSlicer, and Cura.

What carries over

Shape: Kept
Colors: Dropped
Materials: Dropped
Units: Dropped
Separate parts: Dropped
Exact curves: Dropped

About STEP

STEP (ISO 10303 STEP). The ISO standard for exchanging exact CAD solids. Faces are true curves, not triangles, so another CAD program can edit and dimension them.

Units: Explicit. Usually millimeters. Up axis: Z. Opens in Fusion, SolidWorks, Onshape, FreeCAD, and Inventor.

About STL

STL (Stereolithography). The default 3D printing format since 1987: a bare list of triangles. Every slicer reads it, but it has no units, no color, and no parts.

Units: None in the file. Slicers read the numbers as millimeters. Up axis: Z. Opens in Bambu Studio, PrusaSlicer, Cura, OrcaSlicer, and Blender.

Questions

Which quality should I pick?: Normal suits most prints. Pick fine for large round parts, where flat facets would show at a 0.2 mm layer, and coarse when the file has to stay small. The setting changes the triangles, not the size: the part measures the same either way.
What is the difference between STEP and STL?: STEP stores exact surfaces, units and separate parts, for CAD programs and machining. STL stores triangles with no units, for slicers. Design and share in STEP, print from STL.
Does it convert .stp files and assemblies?: Yes. .stp and .step are the same format. An assembly converts with every solid in place, as one STL. To keep the parts apart, for printing them in different colours, convert STEP to 3MF instead.
Can I change the part before printing?: Not in the STL: once it is triangles, the sizes are gone. Change it in your CAD program and export the STEP again, or describe the part to Voloom, which builds a parametric model you can resize and download as STL.
Is the STEP to STL converter free?: Yes. You get 3 runs a month without an account. Sign in with your email, free, and there is no limit.
Is my file uploaded?: No. The file is read and converted in your browser. It never reaches our servers.
Will the STL keep colors and materials?: No. STL has no place for colors, and separate parts, so only the shape carries over.
What units is the STL in?: STEP: Explicit. Usually millimeters. STL: None in the file. Slicers read the numbers as millimeters. The converter does not guess. Use the scale option if the size looks wrong.
How do I open an STL file?: Bambu Studio, PrusaSlicer, Cura, OrcaSlicer, and Blender all open STL.

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