# Sizes, walls and floors

## Outside and inside

The sizes you type are the **outside** of the box. The space inside is:

- **Inside length** = length − 2 × wall
- **Inside width** = width − 2 × wall
- **Inside depth** = height − floor

A 50 × 40 × 30 mm box with 2 mm walls and a 2 mm floor holds 46 × 36 mm, 28 mm deep (46.4 cm³).

## Which wall thickness?

Use a multiple of your line width so the slicer fills the wall cleanly. With a 0.4 mm nozzle (lines about 0.42 to 0.45 mm wide):

| Wall | Lines | Good for |
| --- | --- | --- |
| 0.8 mm | 2 | Light dividers, the thinnest that prints well |
| 1.6 mm | 4 | Everyday storage |
| 2.0 to 2.4 mm | 4 to 5 | Sturdy boxes and bins |

The floor works the same way, in layers: 2 mm is ten 0.2 mm layers.

## Limits

- Each side can be 10 to 300 mm.
- Walls and floor must be at least 0.4 mm.
- Two walls must be thinner than the length and the width, and the floor thinner than the height. The tool tells you which field to fix.