Stuck: Recurring 28 Day Invoice

Hi! I need help! Invoice Ninja can make my life so much easier, but I need to figure something out: I bill in x13 28 day periods a year. When I invoice, I want it to automatically say “Period ___” and the date range for the invoice “xx/xx/20xx - xx/xx/20xx” within the invoice so my clients know for what period they are paying for. I see how to set it to bill in 28 day cycles. I just don’t know how to include the period # and/or the period of time the bill is for in a recurring invoice. Are there any dynamic variables that can help with that?

Thanks in advance!

Maybe you could configure the invoice date as the start date and the due date as the end date.

We don’t have dynamic variables for the period.