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Your STL is converted on your own computer and never uploaded. Files up to 300 MB are accepted.
STL to GLB Converter
Turn STL print files into GLB models for websites, AR and game engines, at real size in meters.
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Converted in your browser. Files are never uploaded.
Continue with your GLB
Check the GLB before you publish it, or convert the same STL for a modeling app.
How to convert STL to GLB
- 1
Add your STL files
Drop one or more .stl files, binary or ASCII, from your slicer, CAD program or a model site such as Printables. Each STL becomes its own GLB, and several files download together as a ZIP.
- 2
Check the size
STL is read as millimeters and written as meters, the unit glTF uses, so a 120 mm part is 0.12 m in AR. Turn on Resize longest side to change it.
- 3
Download the GLB
Save an indexed binary glTF, Y-up, with a neutral grey material, ready for Google's model-viewer, three.js, Babylon.js, Blender or Godot. Each mesh is named after its file.
Why use this STL to GLB converter
Built for taking print files to web pages, AR and game engines.
Size shown before you export
Each STL sits on a build plate with its dimensions in millimeters or inches and its triangle count, so you know the scale first.
Crisp edges, smooth curves
Edges sharper than 40 degrees keep split normals, so flat CAD faces stay crisp while curved surfaces shade smoothly.
Resize before you export
Enter the longest side in millimeters to scale a part up for display or down to fit a scene.
What changes when STL becomes GLB
The surface carries over triangle for triangle. GLB adds what web viewers expect: meters, Y-up, shared vertices, normals for smooth shading and a material, all in one binary file.
Kept
- Every triangle of the surface
- Real size, from millimeters to meters
- Orientation, turned from Z-up to the Y-up glTF uses
- Smooth curves and crisp edges on flat faces
Left behind
- Facet normals stored in the STL (recomputed)
- The 80-byte header text
- Per-facet colors some exporters hide in spare bytes
- Solid names inside ASCII STL files
STL to GLB questions
Answers about AR, the grey material, file size and cost.
Why convert STL to GLB?
STL is made for slicers: bare triangles with no unit, color or scene. GLB, the binary form of glTF, is the standard for 3D on the web. Google's model-viewer, three.js, Babylon.js and Android's Scene Viewer load it directly, and it carries real-world units and a material. Blender and Godot import it natively.
Will the GLB work in AR?
Yes on Android, where Scene Viewer opens GLB files. On iPhone and iPad, AR Quick Look needs USDZ, which model-viewer can create from the GLB in the browser. Because the GLB is in meters, the model appears at its real size: a 60 mm figurine shows up 6 cm tall on your desk.
Why is the GLB grey?
STL stores no color, so the GLB gets one neutral grey material with a matte finish. Change the color or add textures in Blender, or set the material in your web viewer or game engine. If you need color from the start, export glTF from the CAD or modeling app that made the part.
Will the GLB be smaller than the STL?
Usually. STL repeats every corner for each triangle that touches it, while GLB stores each vertex once and refers to it by index. Smooth organic models shrink the most; CAD parts with many hard edges shrink less, because those edges keep separate normals.
Is the STL to GLB converter free?
Yes. It is free with no sign-up and no limit, and the conversion runs in your browser, so your STL never leaves your device. Files up to 300 MB are accepted.