Yes, Michigan does accept a federal extension for individual income tax. If you filed IRS Form 4868 to extend your federal return, the Michigan Department of Treasury automatically extends your state filing deadline to match, which for calendar-year filers is typically October 15. One catch matters more than any other: the extension gives you more time to file, not more time to pay. Any Michigan tax you owe is still due by the original April deadline.1Michigan Department of Treasury. Form 4 – Instructions for Application for Extension of Time to File Michigan Tax Returns
How the Federal Extension Carries Over
If you have a valid federal extension and you don’t owe additional Michigan tax, you don’t need to file anything extra with the state. Treasury treats the federal extension as an automatic state extension and pushes your Michigan deadline to the same date the IRS granted you.1Michigan Department of Treasury. Form 4 – Instructions for Application for Extension of Time to File Michigan Tax Returns
The automatic carryover covers paperwork, not money. If you expect to owe Michigan tax beyond what you’ve already paid through withholding or estimated payments, that payment still has to reach the state by the original April due date.
When You Still Need Michigan Form 4
Two situations call for filing Michigan Form 4 (Application for Extension of Time to File Michigan Tax Returns): you haven’t filed a federal extension, or you owe additional Michigan tax and need to send payment with your request. Even without a federal extension, Treasury will generally grant individual filers a six-month extension through Form 4.1Michigan Department of Treasury. Form 4 – Instructions for Application for Extension of Time to File Michigan Tax Returns
If you make your extension payment electronically through Treasury’s e-Services portal, you don’t need to mail Form 4 at all. Otherwise, mail the completed form (or a copy of your federal extension) with any payment to the Michigan Department of Treasury, PO Box 30774, Lansing, MI 48909. The form and any payment must be postmarked on or before the original filing deadline to count as timely. If you file Form 4, don’t also send a copy of the federal extension; keep that copy for your records.1Michigan Department of Treasury. Form 4 – Instructions for Application for Extension of Time to File Michigan Tax Returns
Paying What You Owe by April
This is where most filers get caught. An extension to file is not an extension to pay, and that rule holds whether your extension comes from the automatic federal carryover or from a Michigan Form 4. Any tax owed must be paid by the original April due date, and late-filing penalties and interest begin accruing from that date on any unpaid balance.1Michigan Department of Treasury. Form 4 – Instructions for Application for Extension of Time to File Michigan Tax Returns
Michigan’s individual income tax rate is 4.25%. If you can estimate your total income for the year, subtract any withholding on your W-2s and any estimated payments you’ve already made. If the result suggests you still owe, send that amount with your extension request. Overpaying slightly beats underpaying, because Michigan refunds the excess when you file your actual return.
What It Costs If You Don’t Pay On Time
Michigan uses a single penalty structure that applies whether you file late, pay late, or both. The penalty is 5% of the unpaid tax for the first two months (or any part of that period). After two months, an additional 5% is added for each month or partial month the return remains unfiled or the tax remains unpaid, up to a maximum penalty of 25%.2Michigan Department of Treasury. What Are the Penalty Charges for Failure to File or Pay On a $2,000 unpaid balance, that works out to $100 for the first two months combined and an additional $100 for each month after, capped at $500.
Interest also accrues on the unpaid tax from the original due date until you pay. Michigan calculates it at one percentage point above the adjusted prime rate charged by major commercial banks, recalculated every six months and effective on January 1 and July 1.3Michigan Legislature. Michigan Compiled Laws 205-24 – Failure to File or Pay Tax For the first half of 2026, the annual interest rate is 8.48%.4Michigan Department of Treasury. Revenue Administrative Bulletin 2025-13
The penalty can be waived if you show reasonable cause for the delay and the failure wasn’t due to willful neglect. Interest is not waivable; it accrues automatically regardless of the circumstances.3Michigan Legislature. Michigan Compiled Laws 205-24 – Failure to File or Pay Tax
Filing Your Return After the Extension
When you file your MI-1040 during the extension period, include a copy of your federal or state extension with the return.5Michigan Department of Treasury. What Is an Extension If you sent a payment with your extension request, report that amount on line 31 of your MI-1040 so you get credit for it. Skip that step and the state may show you as underpaid.
The extended deadline itself is firm. If October 15 passes without a filed return, the late-filing penalty runs from the original April due date, not from October, so you could face the full 25% penalty plus months of accumulated interest by the time Treasury contacts you.
Disaster-Related Extensions Work Differently
Michigan occasionally grants additional relief for residents affected by federally declared disasters. In March 2026, for example, Treasury extended deadlines for taxpayers in several southwest Michigan counties after a severe weather emergency.6Michigan Department of Treasury. Tax Extension Relief Available to Taxpayers in Southwest Michigan Affected by Severe Weather Emergency These extensions typically align with IRS disaster relief dates and apply to both filing and payment deadlines, which is the meaningful difference from a standard extension. If a federally declared disaster affects your area, check Treasury’s website for the specific announcement, since covered counties and extended dates vary by event.