A Missouri tax extension gives you until October 15, 2026 to file your 2025 state income tax return, and in most cases you don’t have to do anything separate to get it. If you already filed a federal extension on IRS Form 4868 and don’t owe any additional Missouri tax, the state extension is automatic. If you do expect to owe, you need to file Form MO-60 and send your payment by the original April 15, 2026 deadline. The extension buys time to file paperwork. It never buys time to pay.
The Automatic Extension for Filers Who Don’t Owe
Missouri keeps this straightforward. If you filed for a federal extension and your Missouri withholding and estimated payments already cover what you owe the state, your Missouri deadline moves automatically to match the federal one.1Missouri Revisor of Statutes. Missouri Code 143.551 – Extension of Time for Filing and Payment No state form is required up front. When you eventually file your Missouri return, attach a copy of your federal Form 4868.2Missouri Department of Revenue. Individual Income Tax FAQs
This automatic extension applies to individuals, businesses filing composite returns, and fiduciaries.3Missouri Department of Revenue. 2025 Application for Extension of Time to File The only condition is that you genuinely owe no additional Missouri tax. If you run the numbers and realize you do owe, the automatic extension isn’t enough on its own.
When You Need to File Form MO-60
Form MO-60 is the Application for Extension of Time to File, and you need it any time you expect a balance due to Missouri. The form must be submitted with payment on or before the original return due date, which is April 15, 2026 for the 2025 tax year.3Missouri Department of Revenue. 2025 Application for Extension of Time to File
To fill it out, you need your Social Security number (and your spouse’s if you’re filing jointly), your current mailing address, and an estimate of your total Missouri tax liability for the year. Subtract withholding, estimated payments, and any credits already applied. The remainder is what you pay with the form. The same MO-60 covers individual returns (MO-1040), fiduciary returns (MO-1041), and composite returns, so check the correct box.
Mail the form and payment to:
Missouri Department of Revenue
P.O. Box 3400
Jefferson City, MO 65105-34003Missouri Department of Revenue. 2025 Application for Extension of Time to File
Certified mail is worth the small cost because it gives you proof of the submission date if the state later questions timeliness.
Payment Is Still Due on April 15
This is where filers get caught. An extension moves your filing deadline to October 15, but your payment is still due April 15. Missouri law states the payment date is calculated “without regard to any extension of time for filing the return.”4Missouri Revisor of Statutes. Missouri Code 143.511 – Time and Place for Filing Returns and Paying Tax, Exception The extension statute itself requires you to send “the amount properly estimated” as your tax by the original deadline.1Missouri Revisor of Statutes. Missouri Code 143.551 – Extension of Time for Filing and Payment
Payments sent with Form MO-60 get credited against your final liability, which reduces or eliminates the interest and penalties you’d otherwise owe when you file the completed return. The practical rule: pay as much of your estimated balance as you can by April 15, even if you’re not sure the number is exact. Every dollar paid on time is a dollar not accruing interest.
There is one narrow exception. If you also received a federal extension of time to pay (not just to file), you can submit a copy to the Department of Revenue and Missouri will extend your state payment deadline to match.1Missouri Revisor of Statutes. Missouri Code 143.551 – Extension of Time for Filing and Payment Most filers don’t have this; a standard Form 4868 extension of time to file does not include it.
What Late Payment and Late Filing Cost
Missing a deadline triggers up to three separate charges in Missouri: interest, a failure-to-pay addition, and a failure-to-file addition.
Interest
Interest accrues on any unpaid balance from the original April due date until the day you pay in full, regardless of whether an extension is on file. The rate is set under a separate statute and can change quarterly.5Missouri Revisor of Statutes. Missouri Code 143.731 – Interest on Underpayments Balances under one dollar aren’t charged interest.
Failure-to-Pay Addition
If the balance isn’t paid by the original April deadline, the Department of Revenue applies a 5% addition to tax.2Missouri Department of Revenue. Individual Income Tax FAQs Separate additions apply to deficiencies caused by negligence or fraud under Missouri Code 143.751.6Missouri Revisor of Statutes. Missouri Code 143.751 – Failure to Pay Tax
Failure-to-File Addition
Miss the October 15 extended deadline without filing and Missouri adds 5% of the unpaid tax for the first month, plus 5% for each additional month or partial month the return stays outstanding, capped at 25%.7Missouri Revisor of Statutes. Missouri Code 143.741 – Failure to File Tax Returns This is the penalty the extension is designed to prevent. File by October 15 and it never applies, even if you still owe a balance.
Military Deployments and Disaster Declarations
Two situations change the deadline rules entirely.
If you serve in a combat zone, a qualified hazardous duty area, or a contingency operation, Missouri follows the federal rule: your filing and payment deadlines are automatically extended by 180 days after you leave the designated area or the area loses its combat zone designation. On top of those 180 days, you get back whatever time remained on your original deadline when you entered the zone. A deployment that began on March 1, with 45 days remaining before an April 15 deadline, produces 180 plus 45 days after you leave. The Department of Revenue charges no interest or penalties during the entire extension period.8Missouri Department of Revenue. Military Reference Guide The relief also covers qualifying service outside the combat zone when you’re in direct support and receiving hostile fire or imminent danger pay.
Federally declared disasters produce similar postponements. The IRS identifies affected taxpayers automatically and applies relief without a separate request.9Internal Revenue Service. IRS Announces Tax Relief for Taxpayers Impacted by Severe Storms Because Missouri’s automatic extension tracks the federal deadline, any federal disaster postponement that moves your federal deadline moves your Missouri deadline too. If a disaster has been declared in your county, check both the IRS disaster relief page and the Missouri Department of Revenue site for the specific dates and covered areas.