A small slicer that lives in a browser tab.

What STLToGcode is

STLToGcode is a free online tool that converts 3D models in the STL format into G-code, the instruction set a 3D printer follows. You add a model, choose a printer and a filament, adjust the print settings if you want to, and download a .gcode file.

Strictly speaking it is slicing rather than file conversion: the model is cut into thin layers and each layer is turned into movements, temperatures and extrusion amounts for a specific machine.

Why it exists

Most slicers are large desktop programs. That is fine when you own the computer, but not when you only need to prepare one file quickly, are on a shared or restricted machine, or don't want to install software to test a single model. STLToGcode was built for those moments: open a page, slice, download.

Private by design

Your STL file is read and sliced inside your browser. It is never uploaded, so the model stays on your device.

Free, with no account

No sign-up, no login and no paywall. Open the page, add a model and slice it.

Nothing to install

The slicing engine loads with the page, so it works on a locked-down school or office computer as well as your own.

Honest about limits

It is a slicer for turning models into G-code, not a replacement for tuning your printer. We say what it can and can't do.

How it works

Slicing is done by CuraEngine, the open-source engine behind the Cura desktop slicer, compiled to WebAssembly through the open-source cura-wasm project. When you open the site, your browser downloads the engine and the printer profiles as ordinary static files. From then on the work happens on your own processor:

1. Your STL is parsed and checked in the browser, then shown in a 3D preview.
2. You pick a printer and material profile and tune the print settings.
3. The slicing engine runs locally and produces G-code plus a time and filament estimate.
4. You download the result, or read it as text in the page.

Because everything is local, speed depends on your device. Large or very detailed models slice more reliably on a desktop or laptop than on a phone.

What it is not

• Not a printer controller. It produces a file. Sending it to your printer, and checking that the file suits your machine, is up to you.
• Not affiliated with other slicers. STLToGcode is made independently and is not connected to Cura, Ultimaker, PrusaSlicer, Bambu Studio or any printer maker. Those names belong to their owners and are used only to describe compatibility.
• Not a guarantee. Always review the profile, temperatures and toolpaths before you start a real print. See our Terms and Conditions.

Open-source credits

This site stands on open-source work. Slicing is powered by CuraEngine, used under the AGPL-3.0-or-later license, via cura-wasm. The 3D preview uses Three.js. Source and license details for CuraEngine are available at github.com/Ultimaker/CuraEngine.

Get in touch

Found a bug, missing a printer profile, or have an idea? Write to [email protected] or visit the contact page. Our Privacy Policy explains exactly what is and isn't collected.