STL Tools for 3D Printing & Format Conversion

STLSite is a free, browser-based toolkit built around a single file format: STL, the near-universal way 3D models are shared for printing, scanning, and CAD interchange. Instead of installing a slicer for one job and a format converter for another, STLSite puts a real STL to G-code slicer and nine STL file converters —OBJ, 3MF, GLB, glTF, STEP, PLY, DXF, FBX, and SVG— on one site, each running entirely on your own device. There's nothing to download, no account to create, and no file size gate hiding behind a paywall.

Convert STL to G-code Online, Free

The most common reason people land here is to convert STL to G-code before sending a model to a 3D printer. STLSite's STL to G-code converter isn't a simplified stand-in — it's a real slicing engine (a CuraEngine build compiled to WebAssembly) running inside your browser tab. Upload your .stl file, choose a printer profile, and the tool automatically checks whether your model fits the build volume before you slice. From there you can adjust the print settings that actually change how a part comes out — layer height, infill density and pattern, wall count, print speed, and support generation — or just accept sensible defaults for your chosen printer and material. When you click Slice, the STL to G-code slicer processes your mesh locally and hands back print time and filament estimates alongside the finished .gcode file, ready to copy onto an SD card or send to your printer over the network. Because everything happens client-side, converting STL to G-code online here works the same whether you're on a fast desktop or a laptop on a coffee-shop connection — your model never has to travel over the internet to get sliced.

Nine Ways to Convert an STL File

Slicing isn't the only thing people need to do with an STL. Sometimes the geometry is right and the printer isn't the destination — you need the same triangle mesh in a different container. STLSite's STL to OBJ converter and STL to PLY converter handle the two most common "plain geometry" formats: Wavefront OBJ, readable by almost every 3D application ever written, and the Stanford Triangle Format (PLY), a staple of 3D scanning and mesh-processing tools like MeshLab and CloudCompare. Both conversions are lossless — STL only ever describes triangles, and OBJ and PLY store the exact same triangles back out, so nothing about the shape changes.

If your next stop is a different slicer rather than a generic 3D app, the STL to 3MF converter produces a 3D Manufacturing Format package that modern slicers such as Cura, PrusaSlicer, and Bambu Studio accept directly in place of STL. For real-time rendering, AR, and web or game-engine use, the STL to GLB converter and STL to GLTF converter wrap your mesh as glTF — GLB as a single compact binary file, GLTF as a human-readable JSON file with the geometry embedded inline — both of which drop straight into tools like<model-viewer>, iOS AR Quick Look, and most Android AR viewers.

Engineering and fabrication workflows get their own pair of converters. The STL to STEP converter outputs a spec-valid STEP (ISO 10303) file for CAD interchange, and the STL to DXF converter writes each triangle as a 3DFACE entity in a DXF R12 file readable by virtually any CAD, CAM, or laser-cutter package. Both are honest about what a triangle mesh actually is: STL carries no curve or surface information, so these converters output a faceted representation of your geometry rather than pretending to reconstruct a smooth parametric solid that was never there to begin with. For animation, VFX, and game-development pipelines, the STL to FBX converter writes ASCII FBX 7.4, the well-documented text form of FBX that Blender, Unity, and Unreal all import cleanly. And when all you need is a picture rather than geometry, the STL to SVG converter renders a lit, shaded snapshot of your model — using the same camera angle and lighting as the live 3D preview — and embeds it inside an SVG file you can drop into a document or web page.

Why Run Everything in the Browser?

Every tool on STLSite parses and processes your STL file locally, using WebAssembly and the browser's own 3D rendering pipeline instead of a server. That means your model never leaves your device just to be sliced or converted — there's no upload step to wait on, no server storage to worry about, and no account required to unlock full functionality. It also means the tools work the same on any modern desktop or laptop browser, without installing separate slicer software or command-line converters for each file format. Slicing is the one operation that benefits from more CPU headroom, so very large or highly detailed models will generally slice faster on a desktop machine than on a phone — but the interface itself adapts to any screen size.

Who Uses STLSite?

Hobbyists preparing a downloaded model for their first 3D print use the STL to G-code slicer; makers moving a design between Cura, PrusaSlicer, and Bambu Studio reach for STL to 3MF; engineers and product designers pulling STL scan data into CAD software use STL to STEP or STL to DXF; and game developers, 3D artists, and AR/web developers bringing a printable model into a renderer, engine, or web viewer use STL to OBJ, GLB, GLTF, PLY, or FBX. All of it is free, with no sign-up, no watermark, and no limit on how many files you convert.