Mississippi calendar and forms

Mississippi runs on the federal calendar. Form 80-105 is due April 15, 2027, the four estimated payments fall on the federal dates, and the extension runs to October 15, 2027. The Department of Revenue asks for no extension form of its own: if you owe nothing or expect a refund, the federal extension covers Mississippi; if you owe, the only thing the Department wants by April 15 is the money, on Form 80-106 or through TAP, because the extension does not extend the time to pay. Interest and penalty run from April 15 on anything unpaid, extension or not.

The form side has one return and a short set of schedules that attach only when they apply. Because Mississippi rebuilds income on its own form rather than copying federal AGI, Form 80-105 is longer than most state returns, but the schedules are few: Form 80-107 lists withholding, Form 80-108 carries itemized deductions, interest and dividends, and adjustments, and Form 80-401 summarizes credits. Most wage earners touch two or three of them. The rest of the list is for people who moved, who work across the state line, who owe estimated tax, or who need to fix a return already filed.

The 2027 filing season, dated

How the extension really works

The 2025 Form 80-100 puts it in one sentence: if you will receive a refund or owe no additional tax, Mississippi allows the same extension of time to file as the federal one. There is no Mississippi extension request. If you owe, the booklet says to send the payment with Form 80-106 by April 15, and adds that “the authorized extension of time to file does not extend the time for payment of tax due.” The Department’s FAQ repeats the point: an extension of time to file does not extend the time to pay. So the Mississippi extension is really a federal Form 4868 plus, if needed, a Mississippi check. Pay what you expect to owe through TAP or on an 80-106 by April 15, finish the return by October 15, and the only cost of filing late is interest on whatever the April estimate missed.

The penalties for getting this wrong are stated in the booklet. Late payment draws interest at 1/2% a month and a late-payment penalty of 1/2% a month, capped at 25%. Failing to file at all costs 5% a month, capped at 25%, with a $100 minimum. The failure-to-file penalty is the expensive one, and the extension is what keeps it off the table.

Estimated payments

Mississippi requires estimated payments when withholding and credits will cover less than 80% of the year’s Mississippi tax and the tax is more than $200. The payments go on Form 80-106, the same voucher used for a balance due, or through TAP, where an estimated payment can be made without a login and with no fee. Underpayment interest is 1/2% a month from each installment’s due date until paid, figured on Form 80-320. Farmers and fishers with two-thirds of their income from farming or fishing are excepted. The booklet states the 80% test and no prior-year safe harbor (verify); anyone whose income jumped in 2026 should pay in on the 2026 figure, not last year’s.

Because retirement income is exempt, the people most often caught are not retirees but the self-employed, owners of pass-through businesses, landlords, and anyone with a large capital gain or a Roth conversion before 59½ that had no Mississippi withholding. A Mississippi resident with wages from a state that has no income tax is another common case: the employer withholds nothing for Mississippi, and the whole year’s tax comes due at once.

The forms, in the order a filer meets them

Filing, paying and checking a refund

Nearly every Mississippi return is e-filed with the federal return. The Department encourages it: its FAQ says e-filing can shorten the refund wait by eight weeks, and the booklet says a complete and accurate e-filed return may be refunded in 7 to 10 business days, against six to eight weeks for a paper return. Direct deposit is available on an e-filed return, and on paper by completing page 3 of the 80-105. Early-season refunds can be slower while the Department runs its fraud screens; the booklet says those checks validate income and credits before refunds are released.

The Department does not run its own free filing program. It lists the commercial Federal/State online products and notes that some are free for qualifying filers, without naming which. Mississippi was not part of IRS Direct File, and no state program replaces it for 2027. What the Department does provide free is TAP, the Taxpayer Access Point at tap.dor.ms.gov: payments for a return, an extension or an estimate, with no fee and no login required for estimates; refund status under “Where’s My Refund?”, which asks for the primary filer’s Social Security number, the tax year and the Mississippi AGI from the most recent return; and, with a registered account, a view of payments the Department has recorded. Card and e-check payments go through the separate ms.gov QuickPay portal, which adds a convenience fee.

Paper returns go to one of two Jackson boxes: refund returns to P.O. Box 23058, Jackson, MS 39225-3058; returns with a payment or no tax due to P.O. Box 23050, Jackson, MS 39225-3050. Checks sent without a return go to P.O. Box 23192, Jackson, MS 39225-3192. Taxpayer assistance is (601) 923-7700, refunds (601) 923-7801, 8 a.m. to 5 p.m. weekdays. District offices are in Biloxi, Hattiesburg, Hernando, Clinton (the Jackson office) and Meridian.