Guides · Reviewed 25 September 2026
STL vs 3MF: which file should I use for 3D printing?
Use STL for a standard single-colour print — it's the universal format and works everywhere. Use 3MF when you need to carry extra information such as colour or exact units, or for a multicolour print. Layer & Loop accepts both, so either is fine for an instant quote.
What each format stores
| STL | 3MF | |
|---|---|---|
| Geometry (the shape) | Yes — a triangle mesh | Yes — a triangle mesh |
| Units / scale | Not stored (unitless) | Stored explicitly |
| Colour | No | Yes (per-object / painted) |
| Print settings | No | Can be included |
| Support everywhere | Universal | Widely supported, newer |
Which should you send us?
- Single-colour part → STL is perfect. It's what most CAD tools export by default.
- Multicolour print → upload a painted 3MF through our custom print form, so the colours come through correctly.
- Worried about scale → a 3MF removes any unit ambiguity because the size is baked in. With an STL, just make sure you exported in millimetres (see preparing an STL).
Either way, our quote tool reads the file in your browser, measures it and shows a model-specific price before you commit — so if the scale looks wrong (a part that should be 5 cm reads as 5 mm), you'll spot it immediately.
Related: How to prepare an STL · Get an STL printed without a printer