This plugin provides a textarea that limits the number of characters a user can add. The limit is cleanly represented by a jQuery UI progress bar.

Atomicsmash

Works with ACF v4 and v5
This plugin provides an Advanced Custom Field textarea that limits the number of characters a user can add. The limit is cleanly represented by a jQuery Ui progress bar. You can define the number of characters on a per field basis.
This has been tested in:
<ul>
<li>ACF – Repeater fields</li>
<li>ACF – Flexible content fields</li>
<li>ACF – Option pages</li>
</ul>

Alternatives to Advanced Custom Fields: Limiter Field

Top alternatives