# GLB to STL converter

> Convert GLB and glTF models to STL or 3MF in your browser, scaled from glTF's metres to the millimetres slicers expect. Free, no upload, no sign-up.

Source: https://freestlviewer.com/glb-to-stl/  
Updated: October 22, 2026

Convert .glb and .gltf models to a printable STL at the right size — glTF's metres become the millimetres your slicer expects. Converted in your browser, never uploaded. The tool is interactive: open https://freestlviewer.com/glb-to-stl/ and drop a file onto the page.

## From web model to printed part

GLB is the format of 3D-asset stores, AR pipelines, AI 3D generators and web
viewers. To print one, a slicer wants STL or 3MF — and at the right scale.

## The metres problem

The glTF 2.0 specification defines one unit as one **metre**. Slicers assume
one unit is one **millimetre**. Converted naively, a 25 cm vase becomes a
0.25 mm speck. This converter preselects **metres** for glTF and GLB and writes
the STL in millimetres, so the vase stays 250 mm.

Some tools export GLB at the wrong scale anyway. The summary shows the size
before you download; if it is 1,000 times off, switch the source unit to
millimetres.

## What is kept

| From the GLB | In the STL | In a 3MF |
| --- | --- | --- |
| All meshes, at their node positions | Yes, merged | Yes, merged |
| Solid base colours | No | Yes |
| Image textures | No | No |
| Animation, skinning, morph targets | No — the rest pose is used | No |
| Lights and cameras | No | No |

## Is it printable?

Models made for screens often are not solid. Look at the summary's
watertightness line:

- **Watertight** — the slicer should handle it directly.
- **Open or non-manifold edges** — common with display models built from
  separate surfaces. Slicers often repair small problems; larger ones need a
  mesh tool. See [watertight and manifold meshes](https://freestlviewer.com/blog/watertight-and-manifold-stl-files/).

Also check thin details: what looks fine on screen may be thinner than your
nozzle can print.

## Compressed GLBs

Draco and Meshopt compression shrink web downloads but are not supported here
yet. If a GLB will not open, re-export it without compression and convert again.

## On a phone

GLB conversion works in a phone browser. The Mes3D app for iPhone, iPad, Mac and
Android opens GLB files directly, shows them in AR, and exports STL, OBJ or 3MF
after resizing or cutting.

## Frequently asked questions

### How do I convert GLB to STL?

Drop the .glb onto this page (for a .gltf, drop it with its .bin and textures or as a ZIP). Metres is preselected because glTF is defined in metres; keep it, choose STL and click Convert and download. The STL is written in millimetres at real size.

### Why is my GLB tiny in the slicer after converting elsewhere?

glTF uses metres, slicers assume millimetres. A 0.2 m figurine converted without scaling arrives as 0.2 mm. This converter multiplies by 1,000 when the source unit is metres.

### Can I convert Draco-compressed GLB files?

Not yet. GLB files that use Draco or Meshopt compression do not open in Mes3D at the moment. Re-export without compression, for example with Blender or the glTF-Transform command line, and convert that.

### Are textures kept?

No — STL is geometry only. Choosing 3MF keeps solid base colours; image textures, animation and skinning are not carried over.