# Indefinite size

A size that depends on the content, like auto height.

## What is an **indefinite size**?

An **indefinite size** depends on the content, like an `auto` height. Percentages of an indefinite size often don't work.

```css
.panel { height: auto; }
.panel .inner { height: 50%; }   /* ignored: 50% of an indefinite height */
```

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

Updated: September 27, 2026

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