glTF to STL Converter

Turn a .gltf scene into a printable STL, converted from metres to millimetres and standing upright. Drop the .gltf with its .bin, or a .zip of the folder.

  • Files stay on your device
  • Free, no sign-up
  • Units and up axis handled
  • Batch and .zip

Drop a glTF file to convert

One file, many, or a .zip

In: STL · STEP · IGES · OBJ · 3MF · GLB · glTF · PLY · FBX · DAE · 3DS · AMF · VRML · ZIP

Converted on your device. Nothing is uploaded.

    How to convert glTF to STL

    1. Drop your glTF files

      Drop the .gltf together with its .bin and textures, or a .zip of the folder.

    2. Check the preview

      The model appears at the size and orientation it will have. Fix the file units, up axis or size under Size, units and orientation if needed.

    3. Choose STL options

      Binary STL by default (smallest, read everywhere). Tick ASCII only if an old tool asks for text STL.

    4. Convert and download

      One file downloads straight away. A batch gives a download per file and one .zip of all of them.

    What carries over from glTF to STL

    Worked out from what each format can store and what this converter writes. Nothing is changed silently: the preview shows the size and orientation before you download.

    Geometry Every triangle is kept at full precision.
    Color Dropped: STL cannot store color.
    Units Converted from metres to millimetres, so it keeps its real size. A 0.05 m part comes out 50 mm.
    Orientation Turned from Y up to Z up, so it stands on the plate in a slicer.
    Objects Merged into one surface: STL has no objects.
    Animation Dropped: the model is written in its rest pose.

    glTF to STL: what actually happens

    A .gltf usually comes with a .bin buffer and texture images. Drop them together, or a .zip, and the converter assembles the scene, merges every mesh and writes an STL in millimetres, Z up. The textures aren't needed for STL, but the .bin is: it holds the geometry.

    glTF's metres become millimetres, so a 0.2 m model prints 200 mm tall. Materials and animation are dropped. Check that the result is watertight before slicing; web models often have open edges and inside faces.

    glTF at a glance

    glTF 2.0 JSON · .gltf

    Stores
    A JSON scene that points at .bin buffers and image files (or embeds them)
    Color
    Full: textures, base colors and vertex colors
    Units
    Metres, fixed by the spec
    Up axis
    Y, fixed by the spec
    File size
    JSON plus buffers; embedded base64 adds about a third
    Opens in
    Web viewers, Blender, three.js, Babylon.js, game engines

    A .gltf is the readable JSON form of glTF 2.0. The geometry usually sits in a separate .bin file and textures in image files, which makes it easy to inspect and edit, and easy to break by moving one file.

    Open glTF files in the viewer

    STL at a glance

    Stereolithography (Standard Triangle Language) · .stl

    Stores
    Loose triangles: three corners and a normal each, binary or ASCII
    Color
    None in the standard
    Units
    None written; slicers assume millimetres
    Up axis
    Z, the slicer convention
    File size
    50 bytes per triangle in binary, about 5 times that as ASCII
    Opens in
    Every slicer, CAD tool and 3D app

    Created by 3D Systems in 1987 for the first stereolithography printers, STL is still the format every slicer and print service accepts. It describes a surface as a list of independent triangles, with no shared vertices, units, colors or scene structure.

    Open STL files in the viewer

    Tips for glTF to STL

    Missing .bin?

    The converter tells you which file the .gltf references. Drop it alongside.

    Set the size

    Use the height option in mm if the glTF's size is arbitrary.

    Single file next time

    GLB keeps everything in one file and converts the same way.

    GlTF to STL FAQ

    Do I need the .bin file?
    Yes, unless the .gltf has its data embedded. The .bin holds the vertices and triangles.

    Is the STL the right size?
    It has the size the glTF declares, converted from metres to millimetres. Many web models aren't built to scale, so set a height if needed.

    Can I convert several glTF files at once?
    Yes, drop each .gltf with its files, or zip each folder.

    Is the converter free? Are there limits?
    Free, with no sign-up, watermark or file count limit. Batches and files of a few hundred MB work on most laptops; the only limit is your device's memory.

    Are my files uploaded?
    No. Files are read and written by JavaScript and WebAssembly in your browser and never sent to PrintPal. The STEP and IGES reader is the only extra download, once, from a public CDN.