If you haven’t filed your 2015 tax return yet, and you have an extension, the due date is October 17th. Keep in mind that there are both a FAILURE TO FILE PENALTY AND A FAILURE TO PAY PENALTY. If you are not filing because you don’t have the money to pay your balance due keep this in mind. Better to file, even with your best estimates (and amend later), than to not file on time. There in also an Installment Agreement you can request if you have a balance due.