If you would like to test your WordPress website for PHP 7 compatibility just follow these steps.
There are many plugins that can be used for this, we will cover installing the PHP Compatibility Checker plugin. If you decide to use a different plugin, be sure you choose one that is actively being maintained.
Note: The length of time required is based on the number of plugins and themes that are being scanned.
There are some limitations and caveats for this plugin that may impact certain WordPress sites. The developer's site has additional details, as well as an FAQ for the plugin.