Mississippi Form 80-180 is used to file an extension.
If you need more time to file your Mississippi return, and you will receive a refund or will not owe any additional tax, Mississippi will allow you the same time that is allowed by your federal extension. If you expect to owe additional tax by the April 15 due date and you need more time to file your Mississippi income tax return, you must pay all of your state tax due with Mississippi Form 80-180 by April 15.
Form 80-180 does not extend the due date for payment of your Mississippi income tax. More time to file does not mean more time to pay your taxes. You will owe interest and penalty from April 15 to date of payment. The interest rate is 1 percent (1%) per month and the penalty rate is of 1 percent (.5%) per month or part of a month from April 15 until the date the final payment is received. Late payment penalty will accrue to a maximum of 25 percent (2 5%). Late payment penalty and interest apply to any unpaid tax after April 15.