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 June 1, 2021. You will automatically have until November 1, 2021 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 June 1, 2021.