Free 3D converter / STL to STEP
Convert STL to STEP, free and online
Turn a .stl file into a .step file. It runs in your browser: no sign-up and nothing to install, and most files never leave your computer.
Drop your STL file here
or choose a file
Free · No sign-up · Converted in your browser · Files up to 1 GB
How to convert STL to STEP
- 1Drop your .stl file
On the converter above, or click to choose it. - 2Check the units
STL files don't store them. Pick millimetres, centimetres, metres or inches so the size is right. - 3Click Convert to STEP
The .step file downloads straight away.
STL vs STEP
STL: STL describes a shape as triangles only: no units, no colours, no curves. It's what 3D printers, slicers and scanners use.
STEP: STEP (ISO 10303) is the CAD exchange format: SolidWorks, Fusion 360, Inventor, CATIA, Creo, Onshape and FreeCAD all read and write it. It describes exact surfaces, not triangles.
A STL has no curves, only triangles, so the STEP is made of the same triangles as flat faces. It opens in SolidWorks, Fusion 360, Inventor, FreeCAD and the rest, and you can measure it and use it as a reference, but its curved surfaces aren't editable features. A closed mesh comes in as a solid; an open one as a surface body.
Other conversions
All conversions →Is the STL to STEP converter free?
Yes, with no sign-up and no limit on the number of files. A free account is only needed if you want to send the model to someone for feedback.
Is my file uploaded?
Most files are read and converted right in your browser and never leave your computer. Very large CAD and mesh files are converted on our server instead, then deleted straight after the converted model is sent back to your browser.
What's the biggest STL I can convert?
Up to 1 GB. Big files take longer, and very large CAD files go through our server, as above.
Can I edit the STEP file in SolidWorks or Fusion 360?
You can open it, measure it and use it as a reference or for simple cuts, but it's made of flat triangular faces, so there are no features or editable curves. For an editable part, rebuild it in your CAD program using the STEP as a guide.
Why does it ask for units?
STL files don't record their unit, so the same numbers could be millimetres or inches. Pick the one the file was made in, and check the size shown, so the STEP comes out the right size.
Converting it to send to a client or supplier?
Send them a link instead. They open the model in any browser, with no account and no CAD program, and click the spot they want changed.