Updated: How to auto-resize a textarea (or other inputs) in pure CSS

Changes

Modern CSS offers the [field-sizing](https://developer.mozilla.org/en-US/docs/Web/CSS/field-sizing) property to allow elements to automatically adjust size (width and/or height) to fit their contents.
The most common use case are textareas which start fairly small (e.g. 2 or 3 rows tall) but grow when users enter longer text.
## Usage
```css
textarea {
  field-sizing: content;
}
```
-That's it! At least in modern Chromium-based browsers.
+That's it!
-> [NOTE "Limited browser support"]
-> Support is still lacking in Firefox and Safari (as of mid 2025). If you want auto-sizing inputs in those browsers, you still need a JavaScript solution.
+## Browser Support
-## Suggested usage
+Since June 2026 this is [supported in all browsers](https://caniuse.com/wf-field-sizing) and part of Baseline 2026.
-I suggest using a small JavaScript library like [autosize](https://github.com/jackmoore/autosize) for browsers that do not support `field-sizing` yet.
+* Chrome/Edge 123 (March 2024)
+* Safari 26.2 (November 2025)
+* Firefox 152 (June 2026)
+
+
+
+## Suggested legacy solution
+
+If you need to support legacy browsers, I suggest using a small JavaScript library like [autosize](https://github.com/jackmoore/autosize).
While at it, I also like to disable manual resizing.
```css
@supports (field-sizing: content) {
  textarea {
    field-sizing: content;
    resize: none;
  }
}
```
```javascript
import autosize from 'autosize'
if (!CSS.supports('field-sizing', 'content')) {
  autosize(element) // simplified; you also need `autosize.destroy` unless you're building an MPA.
}
```
Note how we check for `field-sizing` support in both our CSS and JavaScript. We want neither solution to affect the other.
> [NOTE]
> Unlike `field-sizing`, any JavaScript auto-resizing library likely has issues with elements inside hidden containers or elements that are not yet attached to the DOM.
> When adding changes to your application that may cause such issues, be sure to check in browsers that don't support `field-sizing` if everything still works as expected.