https://www.revenue.wi.gov/DORForms/W-221.pdf
1. Q. Who must file a Wisconsin return?
A. A Wisconsin income tax return must be filed by a legal resident of Wisconsin if:
Filing status is: And the person's gross income (or combined income) was at least Single: Under 65 $10,630 or more 65 or over $10,880 or more
Married Filing Joint: Both spouses under 65 $19,280 or more One spouse over 65 $19,530 Both 65 or over $19,780
Married-Filing a Separate Return: Under 65 $ 9,190 or more each spouse 65 or older $ 9,440 each spouse
Head of Household: Under 65 $13,520 65 or over $13,770
2. Q. What is a person’s "domicile"?
A. "Domicile" is a person’s true, fixed, and permanent home where a person intends to remain permanently and indefinitely and to which, when-ever absent, a person has the intention of returning. It is often referred to as "permanent residence" or "legal residence." A person may be physically present or residing in one locality but maintain a domicile in another. A person has only one domicile at any point in time.
3. Q. Are Wisconsin residents serving in the armed forces liable for Wisconsin income taxes? What if the person is stationed outside Wisconsin or overseas?
A. Yes. Wisconsin residents in the armed forces are liable for Wisconsin income taxes on their entire annual Wisconsin net taxable income, regardless of the income source. If a Wisconsin resident is serving in the armed forces outside Wisconsin, including overseas, the person is liable for Wisconsin income taxes on the entire annual Wisconsin net taxable income, wherever earned, just as if the person was physically present in Wisconsin throughout the year. See Question and Answer 9 for from the link provided for more information on exempt military pay.
A member of the armed forces on active duty who receives military pay from the federal government for services performed while stationed outside the United States may be eligible for a credit of up to $300 against Wisconsin income tax.
4. Q. If I am a Wisconsin resident in the armed forces, is my spouse also liable for Wisconsin income taxes? Or if I am a legal resident of another state stationed in Wisconsin on military orders, is my spouse liable for Wisconsin income taxes?
A. If your spouse is a legal resident of Wisconsin, he or she is liable for Wisconsin income taxes as any other resident, regardless of where he or she resides. If your spouse is a legal resident of another state, he or she is notliable for Wisconsin income taxes on income from personal services performed in Wisconsin if he or she is in Wisconsin solely to be with you while you are in Wisconsin under military orders. See Form W-221, Nonresident Military Spouse Withholding Exemption.
If your spouse is a legal resident of another state, he or she is only liable for Wisconsin income taxes on income from a business conducted in Wisconsin, property located in Wisconsin, a Wisconsin state lottery or a multijurisdictional lottery ticket purchased in Wisconsin, Wisconsin pari-mutuel wager winnings and purses, or winnings from a Native American casino or bingo hall located in Wisconsin.
NOTE: Even though the nonresident spouse’s personal service income (wages) may not be tax-able to Wisconsin, it would be taxable to the nonresident spouse’s state of legal residence.
For further information for Military Personnel who are either residents of Wisconsin or who have been stationed here during the tax year please click here to view Income Tax Information for Active Military Personnel.