A Minnesota state tax return is initially due on April 15, the same day a federal income tax return is due to the Internal Revenue Service. For the 2010 tax year, tax returns are due on April 18, 2011. If you receive an approved Minnesota state tax extension, you will receive an additional six months to file your state return, giving you a new filing deadline of October 15.http://taxes.state.mn.us/individ/pages/other_supporting_content_filing_on_time.aspx

It is important to remember that an approved extension only applies to the actual filing of the tax form. Any tax balance you have with the state will still be due on April 18. If your entire outstanding balance is not remitted before that date, you will be assessed late payment penalties and compound interest until your balance is paid in full.http://www.taxes.state.mn.us/taxes/individ/instructions/m1_inst.pdf

In order to prepare a Minnesota tax extension, you will first need to gather all of your tax-related information. This will be the same documentation that you will need to prepare your tax return when you're ready to file it, so keep it all together to find it easily later. You will need the following:

1. Your total earned income for the year––If you are employed, this will be shown on your Form W-2 or Form 1099 as your total taxable wages. If you are self-employed, you will need to calculate your gross earnings and then subtract any deductible business expenses.
2. Your total unearned income that is also subject to taxation––Among other things, this will include unemployment compensation, bank interest, and retirement distributions.
3. The amount of state income taxes that you paid during the year––For employees, these taxes are usually paid through withholding from paychecks. This will be reported on your Form W-2 as state taxes withheld. For self-employed individuals, this amount will be the total of estimated tax payments you made.
4. A copy of your federal income tax return, if you are filing one
   

If you are submitting a federal return, complete that before beginning your state extension. You will need several figures from your IRS Form 1040 to assess your state tax liability. If you will not be filing a federal return at this time, you may wish to consult a tax professional who can help you to calculate the necessary totals.http://www.taxes.state.mn.us/taxes/individ/forms/m1_onscreen.pdf 

To send in an extension payment, you will also need the following:

1. Your Social Security number
2. Your current mailing address
3. Your spouse's full name and Social Security numberhttp://www.taxes.state.mn.us/taxes/individ/forms/m13_onscreen.pdf 

Now that you have all of the necessary information together, you can begin calculating the amount of state tax you will owe, if any. To do this, you need a paper copy of Form M1 "Minnesota Revenue Individual Income Tax Return". You can download this form and the instruction booklet from the Minnesota Department of Revenue website or you can pick up a copy from your local Minnesota library.http://www.taxes.state.mn.us/taxes/individ/forms/m1_onscreen.pdf 

Be sure to read the tax form instruction booklet carefully before you begin working through the return. This will help you to familiarize yourself with any income adjustments you need to make or any state tax credits you may qualify to claim. If you become unsure about any line on the return, stop and consult the instructions for assistance.http://taxes.state.mn.us/pages/current_forms.aspx#instructions

Begin the form by entering the amount of your wages, pension payments and unemployment compensation from your federal return. Then carry the amount of your federal adjusted gross income from your IRS Form 1040 to line D of your Minnesota return. Enter your federal taxable income on line 1.http://www.taxes.state.mn.us/taxes/individ/forms/m1_onscreen.pdf

Make any income adjustments necessary to calculate your state taxable income on line 10. Then consult the tax table located in the instruction booklet to see how much tax is due for your taxable income bracket. Enter the appropriate amount on line 11 as your tax. Then add any additional taxes you will owe and subtract credits that you are eligible to claim. Deduct your state income taxes already paid through withholding or estimated tax payments. What remains will be either an overpayment (refund) or underpayment (balance due).http://www.taxes.state.mn.us/taxes/individ/forms/m1_onscreen.pdf 

If you are due a refund, you can skip this step. When you are ready to file your return, you will simply do so as normal and you should receive your full refund. On the other hand, if you will owe additional taxes, you need to remit the balance of your outstanding tax by April 18 to avoid late penalties and compound interest.http://www.taxes.state.mn.us/taxes/individ/forms/m13_onscreen.pdf

To make a tax payment, you have several options. You can choose to make your payment electronically through the Minnesota Department of Revenue website or via the state toll-free number. If you prefer to make your payment via credit card, you can do so through an outside service for an additional fee.http://www.taxes.state.mn.us/taxes/individ/forms/m13_onscreen.pdf

If you will be remitting your payment by check or money order, you will need to complete Form M13 "Minnesota Revenue Income Tax Extension Payment".http://www.taxes.state.mn.us/taxes/individ/forms/m13_onscreen.pdf You can download this form from the Minnesota Department of Revenue website or obtain it from your library. Complete the voucher by filling in your name and Social Security number, as well as your spouse's, if applicable.http://taxes.state.mn.us/Forms_and_Instructions/m13_web_10.pdf 

Enter your current mailing address and the amount of the tax payment you will be making with the voucher. Be sure to send in the payment and voucher by April 18. If you are unable to pay your entire balance, send in what you can and then contact the Department of Revenue about establishing a payment plan.http://taxes.state.mn.us/Forms_and_Instructions/m13_web_10.pdf 

To avoid any last minute filing, you should begin working on your Minnesota state return as soon as you remit your payment.