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How to File a Missouri Tax Amendment

Missouri State Taxes
amend Missouri taxes
Missouri
"The Show-Me State"

When Do I Have to File My Missouri Tax Amendment?

Your amended Missouri state tax return should be filed within 3 years of the filing deadline for the original tax return, or 2 years from the time when tax was paid (whichever is later).

How Do I Correct My Accepted Missouri Tax Return or File a Tax Amendment For Missouri?

If the taxpayer amended the federal income tax return or another state's income tax return due to changes in income, then a Missouri state income tax amendment form must be filed. Here's how: 

  1. Download and fill out Form MO-1040.
  2. Print your amended return and mail it to: Department of Revenue, P.O. Box 3370, Jefferson City, MO 65105-3370.

Missouri State Tax Amendment Forms (Download, Complete, Print Out, and Mail)

Missouri doesn't have a designated form for filing an income tax amendment. Therefore you must fill out Form MO-1040 Individual Income Tax-Long Form, marking the box on page 1 that says "amended return".

Form (Tax Year) Description
Form MO-1040 (2016) Missouri Individual Income Tax Return Long Form
Form MO-1040 (2015) Missouri Individual Income Tax Return Long Form
Form MO-1040 (2014) Missouri Individual Income Tax Return Long Form
Form MO-1040 (2013) Missouri Individual Income Tax Return Long Form
Form MO-1040 (2012) Missouri Individual Income Tax Return Long Form
Form MO-1040 (2011) Missouri Individual Income Tax Return Long Form

How Do I Check My Missouri State Amended Return Status?

Call the Missouri Department of Revenue at 573-751-3505.

What Are the Penalties, Interest, and Fees Related to Missouri Tax Amendments?

There are several penalties that can be imposed by the Missouri Department of Revenue, including failure to file penalty and failure to pay penalty. The failure to file penalty is imposed when the taxpayer fails to file a tax return by the specified deadline. The penalty is 5% of the tax due per month, but the total penalty will not exceed 25%. A failure to pay penalty is also 5%.

The state of Missouri charges interest on tax delinquencies, or unpaid tax. The following formula is used to compute interest due:

Amount of Tax Due x Interest Rate x Days Late/Days in the Year

Interest Rates on Tax Delinquencies

Year Interest Rate
2011 3%
2012 3%
2013 3%
2014 3%
2015 3%
2016 3%
2017 4%

 

The state of Missouri also calculates interest rate for refunds due to taxpayers. The same formula is used as with tax delinquencies, except the interest is compounded quarter by quarter since 2003.

Interest Rate on Tax Refunds

Year 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter
2011 0.9% 0.9% 0.8% 0.9%
2012 0.8% 0.8% 0.8% 0.8%
2013 0.8% 0.7% 0.7% 0.7%
2014 0.6% 0.6% 0.6% 0.6%
2015 0.6% 0.6% 0.6% 0.6%

Where Do I Mail My Missouri Tax Amendment? - Missouri Mailing Address:

Department of Revenue
P.O. Box 3370
Jefferson City, MO 65105-3370

Missouri Department of Revenue Phone Number: 573-751-3505

Missouri Department of Revenue

Where Do I Find More Info on Missouri Taxes?

How Do I Only File My Missouri Tax Return?

Where is my Missouri State Tax Refund?

Missouri Tax Extension

Missouri State Taxes

What If I Need to Amend My Accepted Federal Tax Return?

Learn how to amend your IRS taxes.