Free tool
Convert STL to GLB, free and in your browser
Turn an STL into a GLB at true size, with smooth shading and a neutral metal, for web viewers, AR and real-time 3D. No install, no account, and the file never leaves your computer.
A free converter from Jart that turns an STL into a GLB in your browser: the STL is read as millimetres, written in metres and turned Y up, with smooth normals and a neutral metal material. Nothing is uploaded and no account is needed.
Drop a STL file here
It is converted to GLB on this computer, in your browser, and never uploaded.
How to convert STL to GLB
- Choose the STL. Drop the .stl file (binary or text) on the box or choose it. It is read in your browser.
- Wait for the mesh. The STL is read with the same reader the studio uses; a large file is read in a background worker.
- Download the GLB. Download the GLB: true size in metres, Y up as glTF requires, with a neutral polished metal.
What changes from STL to GLB
An STL has no unit, so the converter takes its numbers as millimetres, as jewellery, casting and printing files almost always are, and writes the GLB in metres, the unit glTF defines. CAD programs save STL with Z up and glTF is Y up, so the piece is turned a quarter turn about X to stand the same way. The GLB gets smooth vertex normals (from the file, or worked out where the STL has none) and a neutral polished metal you can replace.
An STL is one mesh, so the GLB has one part. A binary STL can hold up to 1,666,666 triangles here, the studio's own limit.
Why convert an STL to GLB?
A GLB is smaller to send, opens in every web viewer and in AR on phones, and carries a material, so the piece looks like metal instead of grey plastic. It is also the format Jart is built around. Keep the STL for the caster or the printer: it is what they expect.
What if the size looks wrong?
The converter shows the size in millimetres before you download. If a ring comes out 25 times too small, the STL was saved in inches; if it is 10 times too small, in centimetres. Export the STL again in millimetres, or convert the original 3DM instead, which says its own unit.
Private by design
Nothing is uploaded. The page reads your file with the browser's file access, converts it on your own computer (the heavy part in a background worker, so the tab stays responsive) and hands the result straight back as a download. Our server sees only that this page was loaded.
Same importer as the studio
The converter uses the studio's own importer, so a file that converts here opens in Jart the same way. What each format keeps; to look at a file first, use the 3D viewer; the other converters: 3DM to STL converter, 3DM to GLB converter.
More free tools
No account, nothing to install. The help centre explains the studio itself.
- Metal weight calculatorGrams and pennyweights of a design in every alloy
- Ring size converterUS, UK, EU and inside diameter, both ways
- 3DM, STL and GLB viewerOpen a CAD file in the browser and turn it
- 3DM to STL converterA Rhino file to a binary STL in millimetres
- 3DM to GLB converterA Rhino file to a GLB with its part names, at true size
Render it photoreal.
Open the same file in Jart, choose the metal and the stones, and render a photograph on your own graphics card. No account needed.