If you live and work in Wisconsin, then your wages are subject to taxation by the state. However, you are only required to file a state tax return if your income reaches a certain level determined by your filing status. The Wisconsin Department of Revenue website provides full details regarding filing requirements.c  

Even if you are not legally required to file a Wisconsin return, it may be to your advantage to do so. This is especially true if you are due a refund, because of overpayments made through the tax year. The only way to know if you will qualify for a refund, though, is to prepare your state return.c The filing deadline for the 2010 calendar year is April 18, 2011.c 

Before you get started on your Wisconsin state tax return, you need to gather all of your relevant tax information and paperwork. This will include the following:

1. Your full name and current mailing address
2. Your Social Security number
3. Your spouse's name and Social Security number, if you are filing a joint tax return
4. A copy of your federal income tax return, if you are filing one
5. Your total earned income in Wisconsin for the year - If you are self-employed, use the total of your earnings minus any qualified business expenses.
6. Your total unearned income that is taxable in Wisconsin, such as interest, dividends, or retirement payments
7. Your total Wisconsin state tax payments - These will either be tax payments you made yourself or taxes that have been withheld from your wages. You can find them on your Form W-2 or Form 1099.c
   

If you are filing a federal income tax return, it is a good idea to complete that form before beginning your state tax return. You will use the federal adjusted gross income, or AGI, to begin your Wisconsin return. This figure can be found near the bottom of page one on your Form 1040. It will also help you to have easy access to most of the above information.c

Once you have all of your necessary information, you should get a copy of the appropriate state tax return for your situation. Wisconsin offers three tax form options, similar to the options provided by the Internal Revenue Service to file a federal return. Which form you will use will depend on your particular circumstances.c 

To file a Wisconsin Form WI-Z, the easy Wisconsin income tax return, you will need to have filed a federal Form 1040-EZ as well. You must also have earned certain wages, have lived in the state the entire year, be under the age of 65, and claim only basic state tax credits.c 

To file using a Form 1A, you must also have meet certain requirements concerning your wages and earnings. You must also take the standard deduction instead of claiming itemized deductions. If you do not meet any of the qualifications to use the shorter forms, you will need to file using a Form 1.c 

All four Wisconsin state tax forms are available for download on the Wisconsin Department of Revenue website. You can download the forms and print them out to complete them by hand. You can also download fill-in forms that you can complete directly on your computer. If you choose to mail them in, you can print them out and file them.c 

If you prefer to file electronically, you can do so by filing through the Department of Revenue website directly. This method is available to all Wisconsin residents without charge. Be sure to print out a paper copy for your records. If you do not have access to the Internet, you can pick up a copy of your state forms at the public library.c

If you are using tax preparation software or a tax preparation website for your federal income tax return, you can choose to complete your state tax return for an additional fee. This method is usually the most convenient, since you can import your necessary information from your federal return directly to your Wisconsin tax return.c

Now that you have the proper tax form, you can start preparing your return. Begin by entering your Social Security number and your spouse's if applicable. Go on to complete the first section by entering your name and address. If you are completing the form by hand, be sure to write clearly and use black ink.c

Enter your federal adjusted gross income. The form directions will tell your where to find this and any other federal information you need from your 1040. At this point, it's a good idea to stop and read the form instructions. If you are using a paper form, the instructions should be include with the form. If you are downloading forms from the Department of Revenue website, you will have the option to download and print the instructions as well.c

The form instructions explain all of the important state tax law changes that you will need to know. The instructions also contain information about various state credits that you may qualify for. As you continue working through the state return, stop at each line and read the section explaining the credit or deduction. This will help you to make use of all of your eligible tax deductions.c

After you figure your taxable income, consult the tax tables located in the instructions to find your tax liability for the year. Enter this amount on the appropriate line. Subtract all of your tax payments for the year, such as any estimated tax payments or withholding from your wages. This will leave either the amount you overpaid (refund) or the amount you underpaid (balance due).c

When you finish completing the return, sign and date it. If you are filing with your spouse, he or she will also need to sign and date it. To file by mail, enclose any payment due in the form of a check or money order and send it with the return to the address listed on the form. Be sure to postmark your return by April 18.c If you are filing electronically, you can pay any balance due over the Internet.