Are my STL files uploaded anywhere?

No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and watch that nothing is sent while the file converts.

Is converting STL to GLTF free?

Yes, without a limit on how many files you convert and with no watermark on the result. Files up to 100 MB are covered by the free plan.

Does converting STL to GLTF lose quality?

STL and GLTF describe content in fundamentally different ways, so the conversion is a reconstruction rather than a copy. The result is faithful, but not byte-for-byte equivalent. Geometry only. Materials, colours, textures and animation are not carried across, and a model placed several times comes back with each copy baked into its own position.

Do I need to install anything to open GLTF files?

No installation is needed for the conversion itself — it runs in the browser you already have. Opening the GLTF afterwards needs whatever software normally handles GL Transmission Format on your device.

STLtoGLTF

Convert STL to GLTF

Up to 3 files at once, 100 with Pro. Mixed formats are fine.

You can convert STL to GLTF free and without an account: drop the file above and the GLTF is ready to download in a second or two. The conversion happens inside your own browser, so the file is never uploaded — it works on Windows, Mac, Linux, iPhone and Android, and keeps working with the network switched off.

What STL and GLTF are for

The 3D printing standard. Triangles only — no colour, no material, no texture.

The 3D format for the web. Geometry, materials and animation in one JSON file.

How to convert STL to GLTF

Drop your STL file onto this page, or click to pick one.
Choose GLTF as the target. The conversion runs inside your browser — the file is never uploaded.
Download the finished GLTF file.

STL vs GLTF: what changes

STL compared with GLTF
	STL	GLTF
Full name	Stereolithography	GL Transmission Format
File extension	.stl	.gltf
Media type	model/stl	model/gltf+json

Quality: The result is a close reconstruction rather than an exact copy. Check it before relying on it.
Where it runs: This conversion runs inside your browser. Your file is never uploaded, and it works with the network disconnected.
What can be lost: Geometry only. Materials, colours, textures and animation are not carried across, and a model placed several times comes back with each copy baked into its own position.

STL to GLTF: common questions

Are my STL files uploaded anywhere?: No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and watch that nothing is sent while the file converts.
Is converting STL to GLTF free?: Yes, without a limit on how many files you convert and with no watermark on the result. Files up to 100 MB are covered by the free plan.
Does converting STL to GLTF lose quality?: STL and GLTF describe content in fundamentally different ways, so the conversion is a reconstruction rather than a copy. The result is faithful, but not byte-for-byte equivalent. Geometry only. Materials, colours, textures and animation are not carried across, and a model placed several times comes back with each copy baked into its own position.
Do I need to install anything to open GLTF files?: No installation is needed for the conversion itself — it runs in the browser you already have. Opening the GLTF afterwards needs whatever software normally handles GL Transmission Format on your device.