Nonresident State Tax Return

A nonresident state tax return is a state income tax return filed by someone who was not a resident of that state during the year but earned income from sources within it. Its function is to report the state-source income, compute the tax on that slice, and reconcile it with any tax the payer withheld. There is no uniform name: New York's form is IT-203, "Nonresident and Part-Year Resident Income Tax Return"; California's is Form 540NR, "California Nonresident or Part-Year Resident Income Tax Return"; New Jersey's guidance simply says to "file a New Jersey nonresident return." This page uses the plainest description of the thing, with "state" in the name because the federal government has a nonresident return too, Form 1040-NR, which is for people who are not U.S. residents at all.

The filing requirement is written state by state, and the two largest states show how differently it can be framed. New York tells nonresidents: "If you are a New York State nonresident you must file Form IT-203, Nonresident and Part-Year Resident Income Tax Return, if you meet any of the following conditions," and the first condition is having New York source income while your "New York adjusted gross income Federal amount column (Form IT-203, line 31) exceeds your New York standard deduction." Two more conditions are about getting money back rather than paying it: wanting "to claim a refund of any New York State, New York City, or Yonkers income taxes withheld from your pay," and wanting to claim refundable or carryover credits. California frames it as a test: "If you are a nonresident of California and received income in 2025 with sources in California, go to Step 1," where Step 1 asks whether gross income exceeds the amount in the state's chart for the taxpayer's filing status, age and dependents, and Step 2 asks the same of adjusted gross income. The thresholds themselves are the state's to publish and can change; the point is that neither state requires a return merely because a dollar of source income exists, and both leave a taxpayer with withheld tax and no return with an unclaimed refund.

New Jersey's rule illustrates the third common trigger, the reciprocal agreement case. Under the Pennsylvania and New Jersey agreement, wages earned across the line are taxed only by the home state, so a Pennsylvania resident working in New Jersey normally files nothing there. But "If you are a Pennsylvania resident and New Jersey Income Tax was withheld from your wages, you must file a New Jersey nonresident return to get a refund," and because "The Reciprocal Agreement covers compensation only," a Pennsylvania resident with New Jersey self-employment income or a gain on New Jersey property "must file a New Jersey nonresident return and report the income received." The nonresident return is how the state hands back tax it should not have kept, and how it collects tax the agreement never covered.

How the tax is computed is the part that surprises people, because the state does not simply apply its rate table to the source income. Both New York and California first compute tax on the whole picture and then scale it. California's instructions put it plainly: use Schedule CA (540NR), columns A through D, "to compute your total adjusted gross income as if you were a resident of California for the entire year," use column E for the income received while a resident plus California-source income received as a nonresident, and then "You determine your California tax by multiplying your California taxable income by an effective tax rate. The effective tax rate is the tax on total taxable income, taken from the tax table, divided by total taxable income." New York's IT-203 has the same architecture in two columns: the Federal amount column carries every item as reported on the federal return, and the New York State amount column carries "all the income included in the Federal amount column that you received from New York State sources." The effect in both is that a nonresident's slice is taxed at the rate the taxpayer's total income would attract, not at the lower rate a small slice would attract on its own.

Two structural points follow. First, both of these forms serve part-year residents as well as nonresidents, which is why their titles say so; a taxpayer who moved into or out of the state during the year uses the same form and the same column mechanics, allocating income by period rather than by source. Second, the nonresident return is one half of a pair. The taxpayer's home state generally taxes all of the same income and allows a credit for the tax paid to the other state, and because that credit depends on the nonresident return's result, the nonresident return is ordinarily completed first. How the credit works, and what happens when residency itself is disputed, belong to the state income tax and residency pages.

1. Identify the source income. Wages for days worked in the state, rental income from property there, business income from operations there and gains on property located there are the usual items. Wages covered by a reciprocal agreement between the two states are generally excluded.

2. Check that state's filing rule. Each state publishes its own trigger: a threshold measured against its standard deduction, a gross-income chart, or simply the presence of taxable source income. Look too at whether tax was withheld; if it was, filing is usually the only way to recover an overpayment.

3. Compute tax as if resident, then scale it. On the state's nonresident form, report total income as the federal return shows it, identify the state-source portion in its own column, compute the tax on the total, and apply the resulting effective rate or income percentage to the state-source share.

4. Then file the home-state return. Report all income there and claim the credit for tax paid to the other state, using the nonresident return's figures.

Consider an example, with an illustrative tax figure that is not any state's real rate. Lena lives in Oregon and earned $150,000 in total, of which $30,000 was for consulting days she worked in California. On Form 540NR she computes her income as if she were a resident; suppose that produces total taxable income of $150,000, on which the state's table gives a tax of $9,000. Her effective tax rate is $9,000 divided by $150,000, or 6 percent, because the rate is the tax on total taxable income divided by total taxable income. She then applies that rate to her California taxable income of $30,000, giving California tax of $1,800. Had California instead taxed the $30,000 slice on its own, a graduated schedule would ordinarily produce a smaller bill; the effective-rate method is what prevents that. Lena's client withheld $2,100 of California tax during the year, so the return produces a $300 refund, and she carries the $1,800 of tax paid onto her Oregon return to claim the credit her home state allows.

Pros

• It is the mechanism that limits the other state's reach to the income sourced there, rather than to everything the taxpayer earned.
• Filing recovers tax an employer or client withheld in excess of what the state may keep, which for many short assignments is most of it.
• The figures it produces feed the home-state credit, so the same income is not taxed twice in full.
• The forms double as part-year returns, so a mid-year move uses the same machinery.

Cons

• The tax on the source income is computed at the rate the taxpayer's total income attracts, not at the lower rate the slice alone would carry.
• Every state's trigger, form and column layout is different, so a person with income in several states prepares several unrelated returns.
• Below-threshold income with withholding is a common silent loss: no return is required, so no refund is claimed.
• The credit on the home-state return may not fully offset the nonresident tax where the two states' rates or rules differ.