docs/extensions/font-size-extension.mdx
---
hide_title: true
title: 'FontSizeExtension'
---
import Basic from '../../website/extension-examples/extension-font-size/basic';
# `FontSizeExtension`
## Summary
Add a font size to the selected text (or text within a specified range).
## Usage
### Installation
This extension is installed for you when you install the main `remirror` package.
You can use the imports in the following way:
```ts
import { FontSizeExtension } from 'remirror/extensions';
```
The extension is provided by the `@remirror/extension-font-size` package.
### Examples
<Basic />
### JSON Content
Initial content can be provided as JSON instead of HTML. Here is how you would provide the size mark.
```tsx
import { FontSizeExtension } from 'remirror/extensions';
import { useRemirror } from '@remirror/react';
const { manager, state } = useRemirror({
extensions: () => [new FontSizeExtension()],
content: {
type: 'doc',
content: [
{
type: 'paragraph',
content: [
{ type: 'text', text: 'Hello ', marks: [{ type: 'fontSize', attrs: { size: '20pt' } }] },
],
},
],
},
});
```
Make sure you include the size unit in the mark because it can throw an error without a unit.
## API
- [FontSizeExtension](../api/extension-font-size)