The past week, I’ve fielded 3 calls about how the taxes work when you live in one state and work in another. (The interest is due to one of the OK casinos having added a hotel which has been hiring.)
The easy part of the answer is there is no change to your Federal return. All of your income, no matter the source or type is reported on a single 1040 (or A/EZ). Information from that return is used by the state to calculate what they will take in taxes from you.
Before I get started on the state info, I have to stress that each state is different and must be reviewed before a tax return is prepared. For any state but Kansas or Okalahoma, I’ll pull out the instructions or my TaxBook States Edition. And I still may check something for KS or OK if it is not a situation I handle a lot.
Most states give you a choice of 3 residency statuses; resident, non-resident and part year resident. Generally, your resident state is where you live, non-resident is a state where you work but don't live and part year is for years where you move from one state to another during the year. BUT-how a state actually defines "resident" can vary and affect a taxpayer's tax. If a taxpayer moves to Kansas during the year, they could have the option of filing as a Kansas resident or as a part year resident. The effect of residency could make a big difference on the tax a taxpayer would pay.
The actual process of preparing a state return depends on the residency status. If a client lived and worked in Kansas for the whole year, I would complete the Kansas return based on information from their Federal return. If they lived in Kansas and worked in Oklahoma (something I see a lot), I would complete the Federal return then the Oklahoma non-resident return. Each state is different but all non-resident returns have you allocate income based on residency. OK figures their tax based on the Federal income +/- special modifications allowed by OK law. From this is subtracted the deductions and exemptions. This is the taxable income and used to calculate the tax. But this can be further reduced by a percentage based on OK income to total income. This percentage is used to figure how much tax is actually due to OK. So, if you lived all year in Kansas but worked in Oklahoma and your only income is from the OK job, your percentage is 100%. But if your spouse works in Kansas or you have other non-OK income, the percent will be lower. Once you have your OK tax, it is offset by withholding leaving a refund or balance due.
Once the non-resident state is completed (in this example OK), the Kansas resident return is done as usual until the credits section is reached. Kansas (and most states) will give you a credit for the income taxes you paid the other state (OK). The methods vary, but your state tax will be reduced. The remaining tax is then offset with withholdings creating a refund or balance due. If the taxpayer worked in more than one state, each state gets their own calculation and their credit is added to the credit(s) from the other states and subtracted from the resident state's tax.
What happens if a taxpayer lived in more than one state during the year? In Kansas, you have 2 options. First, they can file as a part year resident and allocate income to each state and pay tax on that income. Or the taxpayer could file as a resident with the other state(s) treated as a non-resident (the above example). This can be a good tax savings strategy. When I have a client in this position, I figure it both ways to see which is best. Why? If a client moved to Kansas from state with low or no income tax, filing them as a part year resident is much better since the Credit For Taxes Paid Another State will be low or nothing. Each state varies so you have to check their rules.
The other issue, and it is a big issue right now, is what income a non-resident state is allowed to tax. A resident state taxes all the taxpayer’s income and then gives them a credit for the other state taxes. The non-resident state can only tax income earned by the taxpayer in that state. Wages and self-employment income are taxed in state they were earned. Income generated from property in a non-resident state is taxable to that state. That could mean rents and royalties or gain from the sale of that property. But the interest from a bank account is not taxed in the non-resident state, no matter where the bank is actually located. States are beginning to look at part year residents and how they allocate resident income to make sure they are receiving the tax on their share of income received while the taxpayer was a resident.
Having to report income from more than one state can confuse a taxpayer. If they choose not to use a tax professional, they need to read the rules for all states involved. Not just the residency rules but the actual line instructions for the forms. Besides calculating the tax differently, each state has different credits and programs the taxpayer might qualify for which need to be researched.