Extension requests: Iowa does not have an extension form to obtain additional time to file.
To avoid the late-filing penalty, at least 90% of your total tax liability must be paid by April 30, 2019. You will automatically have until October 31, 2019 to file your return. You may, however, owe a penalty for failure to make estimated payments. You will owe interest on any tax due if paid after April 30, 2019.