# Background size

Sets how big a background image is, like cover.

## What does `background-size` do?

`background-size` sets how big a background image is. `cover` fills the whole box, cropping if needed.

```css
.hero { background-size: cover; }
```

Level: Apprentice · [More CSS terms at this level](https://www.ask-codey.com/glossary/subjects/css/apprentice)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/background-size