I developed this plugin to create the calculation of a future date based on the number of days from the current date.
To use the plugin just add the folloing shortcode into your page.
[show_future_date day=”X”]
where X is equal to the number of days forward you wish to display. For example, if you wanted to show the date 20 days from today you would use the following:
[show_future_date day=”20″]
You can download the plugin here.