# Pixel

px: a fixed unit of size on screen.

## What is a **pixel** unit in CSS?

A **pixel** (`px`) is a fixed unit of size on screen. It is the easiest unit to reason about but doesn't grow with the user's font settings.

```css
.avatar { width: 48px; height: 48px; }
```

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

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/pixel