I have a user registration that includes a trial period (in days). Once the user registers, I want the form to calculate the end of the trial period by adding the value of the trial period field and the created_at date. Generally I would do this on the fly using PHP, but I cannot find any way to retrieve the created_at value using PHP. I then tried calculating this by adding [15] + [created-at], but this does not work as the [created-at] shortcode only works in views. Also, I have no clue (and couldn't find any reference) how this would be interpreted, e.g. if [15]=5, how would I tell the calculation that this is days. The reason why I need to know whether the trial period is done - in PHP - is because I want to redirect the user to a payment page. Any ideas on how to implement this would be appreciated.