# STL to USDZ Converter

> See a print in your room before you print it: STL to USDZ for AR Quick Look at true size.

Page: https://printpal.io/convert/stl-to-usdz
Updated: 2026-11-12
Use it: open https://printpal.io/convert/stl-to-usdz in a browser and drop a file. Free, no account, files are processed locally and never uploaded.

The converter turns the STL's millimetres into USDZ metres, stands it on the floor and gives it a neutral material. Open the .usdz on an iPhone or iPad, tap AR, and the part appears at the size it will print.

It is a quick way to check scale, a display stand's footprint or how a figure looks on a shelf before committing filament.

## How to convert STL to USDZ

1. **Drop your STL files.** Drop one or more .stl files, binary or ASCII, or a .zip of them.
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 USDZ options.** Written in metres, Y up, sitting on the floor and centered, which is what AR Quick Look expects.
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

| | Result |
|---|---|
| Geometry | Every triangle is kept at full precision. |
| Color | STL has no color to carry. The USDZ comes out uncolored. |
| Units | Converted from millimetres to metres, so it keeps its real size. A 50 mm part is written as 0.05. |
| Orientation | Turned from Z up to Y up, so it stands upright in web viewers and AR. |
| Objects | Each part stays a separate object or mesh. |

## STL at a glance (Stereolithography (Standard Triangle Language))

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.

- **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

## USDZ at a glance (Universal Scene Description, zipped)

USDZ packages Pixar's Universal Scene Description for Apple's AR Quick Look: tap a .usdz on an iPhone and the model appears in your room at real size.

- **Stores:** A Pixar USD scene and its textures in an uncompressed zip
- **Color:** PBR materials and textures
- **Units:** Metres in this export
- **Up axis:** Y
- **Use:** AR Quick Look on iPhone, iPad, Mac and Vision Pro
- **Opens in:** Safari and Files on Apple devices, Reality Composer, Blender, Omniverse

## Tips

- **Scale check** Set the exact size first; AR is true to scale.
- **Share it** Send the .usdz in Messages; it previews in AR on the other end.
- **Android** Use [STL to GLB](https://printpal.io/convert/stl-to-glb) for Android Scene Viewer.

## FAQ

### Is the AR model true to size?

Yes. Millimetres are converted to metres, which AR Quick Look shows at real scale.

### Does it keep color?

STL has none; the model is a neutral grey.

### Do I need an app?

No. iPhone and iPad open USDZ with the built-in Quick Look.

### 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.

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