Most online stores take care of tax calculations before you can complete your purchase. It is always nice to give your customers the ability to see prices before and after tax. The Including/Excluding Tax Price Toggle plugin for WooCommerce can handle it. It displays a toggle button that your visitors can use to see your prices.
As you can see in the above GIF, when your customers click on the button, your prices are updated to account for the tax they will have to pay. You can change the text, font, and other settings for the button.