Convert STEP to STL
Preparing a CAD assembly for 3D printing or a slicer pipeline. 100% client-side — your files never leave your browser.
Drag and drop, or click to choose a STEP file. It's parsed entirely in your browser — nothing is uploaded.
STL is preselected on this page. Change it, adjust unit scale/axis in Options, or add more files to batch-convert.
Once conversion finishes, download the result directly, or grab the whole batch as one ZIP.
What changes when you convert STEP to STL
- Triangle mesh geometry
- PBR materials
- scene hierarchy / part names
- vertex or material colors
STL cannot represent PBR materials, scene hierarchy / part names, vertex or material colors — those are computed away during export, not silently corrupted.
STEP to STL technical reference
| Source format | ISO 10303 CAD Solid (.step, .stp) |
| Target format | Stereolithography (.stl) |
| Conversion engine | Runs entirely client-side via WebAssembly + Three.js |
| Upload required | No — files are read and converted locally |
STEP to STL FAQ
Is my STEP file uploaded anywhere?
No. The conversion runs 100% inside your browser using WebAssembly and client-side JavaScript. Your STEP file, and the STL file it becomes, never touch a server.
What does converting STEP to STL keep or lose?
Kept: Triangle mesh geometry. Lost: PBR materials, scene hierarchy / part names, vertex or material colors. STL cannot represent PBR materials, scene hierarchy / part names, vertex or material colors — those are computed away during export, not silently corrupted.
Can I convert multiple STEP files to STL at once?
Yes. Drop as many files as you like — they queue and convert one at a time (to keep memory use predictable), and you can download each one individually or all together as a ZIP.
Is there a file size limit?
There's no hard limit — you're bound by your device's available memory. Large batches (50+ files) convert serially to stay within a predictable memory budget.
Do I need to install any software?
No installation, plugins, or account are required. This runs in any modern browser that supports WebAssembly (Chrome, Edge, Firefox, Safari).