If you are unable to complete and file your return by the due date, you may avoid penalty and interest by paying your tax by April 15. Estimate your total tax and pay the amount you owe electronically, by check or by credit and/or debit card. For information on how to pay electronically or by credit card or debit card, see Payment options on the next page. If you pay by check, you must send your tax payment with a completed Form M13, Income Tax Extension Payment, by April 15. Do not send in an incomplete Form M1. To avoid a late filing penalty, you must file your return by October 15.
Military extensions. Military personnel serving in, or in support of, presidentially declared combat zones are allowed the same extensions of time to file and pay their state income taxes as they are allowed for federal taxes. When you file Form M1, enclose a separate sheet stating you were serving in a combat zone.