Michigan Tax Extension Rules and Filing Deadlines

Running out of time before the Michigan deadline? Six more months are available. Michigan asks you to send something for them, though, and what you send depends on whether you already hold a federal extension.

A Michigan tax extension is an extension to file and nothing more. Treasury says so plainly: the extra months move your filing date and leave the payment date where it was.

This page covers the individual taxpayer filing a Michigan individual income tax return on Form MI-1040. For the federal side of the process, see our guide to filing a tax extension, and for everything else Michigan, see the Michigan state tax guide. For other states, start at the state tax extension hub.

How Does a Michigan Tax Extension Work?

Michigan generally allows a six-month extension to file an individual income tax return, moving the extended filing deadline to October 15, 2026, for taxpayers whose original deadline is April 15, 2026. If you receive a federal extension, Michigan automatically extends your filing deadline to the new federal due date.

Michigan Automatically Follows Your Federal Extension

If you obtain a federal extension to file your federal income tax return, you generally do not need to file a separate Michigan extension request. Michigan recognizes the federal extension and extends the deadline for filing your Michigan return to the new federal due date.

Keep a copy of your federal extension, Form 4868, with your tax records in case you need to document the extension.

However, an extension gives you additional time to file, not additional time to pay. If you owe Michigan income tax, you should make the required payment by the original tax deadline to minimize potential interest and penalties. The payment requirement is separate from the extension of time to file.

Without a Federal Extension, You File Form 4

If you have no federal extension, the state extension comes from Form 4, the Application for Extension of Time to File Michigan Tax Returns. Same six months, same payment requirement, different piece of paper.

Detroit Is a Separate Filing

Form 4's instructions carry a line worth reading twice: "Do not use this form for City of Detroit extensions. Use Form 5209 for individual city filing extensions."

Michigan city income tax runs on its own track. If you file a Detroit return, your state extension does not reach it, and Form 5209 is the one that does. Neither form covers the other.

How Do You File a Michigan Tax Extension?

Step 1: Estimate what you owe

Michigan taxes income at a flat 4.25 percent, the rate for both the 2025 and 2026 tax years. Pull your tax documents and income records together, multiply your expected Michigan taxable income by 4.25 percent, then subtract your tax withholding, any quarterly estimated tax payments already made, and any Michigan tax credits you expect to claim.

What remains is your tax balance due, and Michigan wants it with the extension request rather than in October.

Step 2: Pay the balance by April 15, 2026

Treasury is direct about the consequence of sending an extension request without the money: "You may be charged a penalty of 10% or more if the balance due is not paid with your extension request."

Michigan's e-Payments service handles this electronically, by eCheck from a checking or savings account or by credit or debit card. Michigan Treasury eServices also covers Make a Payment, File a Return and Access Tax Records in one place.

Step 3: Send the federal extension copy, or Form 4

Mail the payment with either a copy of your federal Form 4868 or a completed Form 4 to:

Step 4: Keep the receipt and file by October 15

Hold your payment receipt and your filing confirmation together. Then file the completed MI-1040 by October 15, 2026, and file a Detroit return separately if one applies to you.

How Much Should You Pay With an Extension?

Send the full balance. Michigan charges both a penalty and interest on whatever is left, and the penalty grows in steps rather than all at once.

Say your Michigan taxable income leaves you with a $3,000 liability and your withholding covered $2,600. The $400 remainder belongs with your extension request in April, not with your return in October.

Our penalty and interest calculator can help you estimate what a shortfall would cost.

The Penalty Holds Flat for Two Months, Then Climbs

Michigan's schedule on Form 4 starts at 5 percent of tax due. After the second month it increases by an additional 5 percent per month or fraction of a month, to a maximum of 25 percent.

The practical shape of that is a grace period of sorts. Months one and two cost the same 5 percent. Month three is when the charge starts moving, and it keeps moving for four more months before it caps.

Michigan Ties Its Interest Rate to the Prime Rate, Twice a Year

Interest runs on the unpaid balance alongside the penalty. Michigan sets the rate at one percentage point above the adjusted prime rate charged by three commercial banks to large businesses, under section 23(2) of the Revenue Act.

For July 1 through December 31, 2026 that works out to 7.85 percent a year, a daily rate of 0.0002150. Treasury resets it every January 1 and July 1, so the figure that applies to your balance depends on which half of the year you are in.

Michigan Business Tax Extension Basics

Corporations, partnerships and multi-member LLCs extend their federal return on Form 7004. On the Michigan side, Form 4 covers business returns as well as individual ones, and the extension lengths vary by return type.

The payment rule above applies here too. A self-employed taxpayer, freelancer or small business owner filing a personal return uses the individual route on this page rather than the business one.

Do Military Servicemembers Get More Time to File in Michigan?

Yes, and Michigan's combat zone relief differs from its ordinary extension in two ways that matter.

Combat Zone Relief Covers Paying as Well as Filing, and There Is Nothing to Claim

Treasury extends "the deadline for filing and paying" for personnel stationed in a combat zone and for their spouses, running through the whole period in the zone and for 180 days after leaving it.

Filing and paying. An ordinary Michigan extension moves only the filing date; this moves both.

The second difference is that you do not apply for it. In Treasury's words, "there is no requirement for you to certify your presence in a combat zone to qualify for the extension. Your branch of the military reports that information to the Internal Revenue Service for you."

Relief also reaches servicemembers outside a combat zone in defined cases: serving in direct support of combat zone personnel while receiving hostile fire or imminent danger pay, deploying overseas in support of a qualified hazardous duty operation, or being hospitalized outside the United States for an injury from combat zone service.

The combat zone tax extension page covers the federal rules underneath this.

Common Michigan Extension Mistakes to Avoid

• Holding a federal extension and sending nothing. Michigan wants a copy of Form 4868 along with your payment. The federal filing alone does not request the state extension.
• Filing Form 4 when you already have a federal extension. Form 4 is the route for filers without one.
• Assuming your state extension covers Detroit. City filing extensions use Form 5209, and Form 4's instructions say so explicitly.
• Sending the request without the money. Treasury warns of a penalty of 10 percent or more when the balance due is not paid with the extension request.
• Expecting the penalty to stay flat. It holds at 5 percent through the second month, then climbs 5 points a month to 25 percent.
• Using a stale interest rate. Michigan resets on January 1 and July 1 and is at 7.85 percent for the second half of 2026.
• Certifying combat zone service. There is nothing to file. Your branch reports it for you.

Compare Michigan Extension Rules With Other States

State tax extension rules vary across the country. Some states automatically accept the federal extension, while others require a separate form.

• Ohio tax extension
• Indiana state tax extension
• Wisconsin tax extension rules
• Illinois extension deadline
• Ohio tax extension

Filing Your Michigan Extension

Michigan's extension is straightforward once you know it is a two-part errand. Work out your balance at 4.25 percent, send it with either a copy of your federal Form 4868 or a Form 4, and file the MI-1040 by October 15. If you file a Detroit return, handle that extension separately on Form 5209. A licensed tax professional can confirm the estimate if your year was unusual.

File your extension with FileTax.com and we will walk you through the federal side, which is the piece Michigan asks you to send along.