How to convert STL to USDZ
- Drop your .stl file into the box above, or click Choose file.
- Check the 3D preview, size and triangle count.
- Make sure USDZ is selected as the output format. Adjust scale or up-axis if needed.
- Click Download. The .usdz file is created instantly on your device.
Why convert STL to USDZ?
Show a 3D print in augmented reality on an iPhone or iPad: convert the STL to USDZ, then open it in Safari or Files to place it on your desk at real size.
What changes in the conversion
- Units. STL is in metres; USDZ is usually read as millimetres. Small models are scaled ×1000 automatically – you can change this before downloading.
- Up-axis. STL is usually Z-up while USDZ is Y-up; the model is rotated so it stands the right way up. Untick "Convert up-axis" to keep the raw coordinates.
- Geometry is preserved. Every triangle, with all object transforms applied, ends up in the new file.
STL vs USDZ
| STL | USDZ | |
|---|---|---|
| Full name | Stereolithography | Universal Scene Description (zipped) |
| Stores | geometry only | geometry, PBR materials and textures |
| Colour | No | Yes |
| Textures | No | Yes |
| Units | none – most programs read STL numbers as millimetres | stored in the file |
| Exact CAD geometry | No | No |
About the formats
STL (Stereolithography) was created by 3D Systems in 1987 for its stereolithography printers. It describes only the surface of a model as a list of triangles, without colour, materials or units. It is the default file for 3D printing and the format almost every slicer (Cura, PrusaSlicer, Bambu Studio, Chitubox) opens.
USDZ (Universal Scene Description (zipped)) was based on Pixar's Universal Scene Description and adopted by Apple for AR Quick Look. It is an uncompressed zip package with a USD scene and its textures. It is the format iPhone and iPad use to show 3D models in augmented reality straight from Safari and Messages.
Frequently asked questions
Is this converter free?
Yes. You can convert STL to USDZ for free – up to 3 conversions a day, with no sign-up and no watermark. If you need more, Pro gives you unlimited conversions and batch conversion (free for 7 days).
Are my files uploaded to a server?
No. The conversion runs entirely in your browser using WebAssembly and JavaScript. Your model never leaves your computer, which also makes it safe for confidential parts and patient data.
Is there a file size limit?
There is no fixed limit. Files of a few hundred megabytes work on a typical laptop; the practical limit is your device's memory.