When your W-2 shows more than one state in Box 15, you file a separate state tax return for each state listed — and the order matters. Start with the nonresident state, finish with your resident state, and claim a credit on the resident return for the tax you already paid to the other state. Multiple entries in Box 15 mean your employer withheld income tax for more than one state, usually because you moved during the year, commuted across a state line, or worked remotely for an out-of-state employer. You will not pay full tax to every state on the same wages, because nearly every state with an income tax offers a credit for tax paid elsewhere.
What the State Boxes on Your W-2 Actually Show
Boxes 15 through 20 handle all state and local tax reporting. Box 15 shows the two-letter state abbreviation and your employer’s state ID number for each state where wages were withheld. The form has room for two states side by side, separated by a dotted line. If you worked in three or more states during the year, your employer should issue a second W-2 to cover the additional states.1IRS. General Instructions for Forms W-2 and W-3 (2026)
Look right next to each state entry. Box 16 shows the wages that state considers taxable. Box 17 shows how much state income tax was withheld. The Box 16 amount for a given state will not necessarily match your federal wages in Box 1, because each state only taxes the income allocated to it. If you split the year between two states, each state’s Box 16 figure should reflect only what you earned there.
Compare Box 16 for each state against your actual earnings during the time you worked there. Payroll systems sometimes allocate wages incorrectly, especially after a mid-year move or a shift in remote-work arrangements. If the split looks wrong, ask payroll for a corrected Form W-2c before you file. The IRS requires employers to issue corrections “as soon as possible” after discovering an error.2IRS. 2026 General Instructions for Forms W-2 and W-3
Figure Out Your Status in Each State
Before touching any state form, decide what each state considers you. That label controls which return you file and how your income gets divided.
- Resident: Your permanent home was in that state for the whole year. It taxes all your income from every source.
- Nonresident: Your home is elsewhere, but you earned income within that state’s borders. It taxes only the in-state income.
- Part-year resident: You moved into or out of the state mid-year. You’re treated as a resident for the months you lived there and a nonresident for the rest.
The most common Box 15 scenario is simple: you lived in one state all year and commuted to work in a neighboring one. That makes you a resident of your home state and a nonresident of the work state. You file a full resident return at home (reporting all income) and a nonresident return with the work state (reporting only what you earned there). If you relocated mid-year, you’re a part-year resident of both the old and new state, though some states will still claim tax on income you continued to source there after leaving.
The 183-Day Rule
Many states use a physical-presence test to decide whether you count as a “statutory resident.” If you spend more than 183 days in a state during the year and maintain a home there, that state can classify you as a resident and tax your worldwide income, even if you consider another state your permanent home. People who split time between two residences or travel often for work should keep day-by-day records. In a residency dispute, the burden of proof falls on you.
Military Spouse Exception
If you’re the spouse of an active-duty service member and you moved because of military orders, federal law protects your tax residency. Under the Servicemembers Civil Relief Act, you and your service member can elect any of three states for income tax purposes: the service member’s legal residence, your own legal residence, or the service member’s permanent duty station.3Office of the Law Revision Counsel. 50 USC 4001 – Residence for Tax Purposes If your W-2 shows withholding for a state you moved to on orders, you can file a nonresident return there to recover the incorrectly withheld tax.
File the Nonresident Return First
When you owe returns to multiple states, complete the nonresident return before the resident return. Your resident state needs a finished tax figure from the nonresident return to calculate your credit for taxes paid elsewhere. Without that number in hand, you cannot fill in the resident return correctly.
On the nonresident return, report only the income you earned in that state. Start with the Box 16 wages for that state, then add any other income sourced there. The form will ask for your total income from all sources and then apply the ratio of in-state income to total income against the state’s tax rates. Every state with an income tax provides a nonresident or part-year resident form; names and numbers vary.
Once you’ve completed and filed the nonresident return, keep a copy along with proof of any payment. You’ll attach both to your resident return when you claim the credit.
The Credit for Taxes Paid to Another State
Your home state taxes everything you earn, no matter where you earned it. To keep the same wages from being taxed twice, nearly every state with an income tax offers a credit for tax you paid to another state. You claim it on your resident return, usually on a dedicated schedule, and most states require you to attach a copy of the completed nonresident return.
The credit equals the lesser of two amounts: what you actually paid to the other state, or what your home state would have charged on that same income. That cap means you always end up paying the higher of the two states’ effective rates on the overlapping income, but never both rates in full.
Here’s how the math works. Say your work state charged 5% on $50,000 of income ($2,500) and your home state would charge 4% on that same $50,000 ($2,000). Your credit is limited to $2,000, the home state’s tax on that income. You pay $2,500 total, all of it to the work state, not $4,500 to both. In the reverse case, where your home state’s rate is higher, the credit fully offsets what you paid to the work state, and your home state collects the difference.
The credit is not refundable. If you paid more to the nonresident state than your home state would have charged on the same income, the excess is gone. This hurts most when the work state’s rates are noticeably higher than the home state’s.
When Your Home State Has No Income Tax
Several states don’t tax wage income. If you live in one and work in a state that does, you owe tax to the work state with no credit available at home, because there’s no home-state liability to offset. Your total state tax burden equals whatever the work state charges. Remote workers whose employer’s state withholds income tax are often caught off guard by this.
Reciprocal Agreements Can Simplify Things
About 16 states and the District of Columbia have reciprocal agreements with at least one neighbor. If you live in one partner state and commute to work in the other, you owe income tax only to your home state. The work state agrees not to tax your wages.
To make that happen, you file a certificate of nonresidence (sometimes called an exemption form) with your employer at the start of employment or after a move. The form tells payroll to stop withholding for the work state.
Employers sometimes withhold for the work state anyway, either because the exemption form wasn’t processed in time or because payroll didn’t know about the agreement. If that’s what your W-2 shows, file a nonresident return with the work state to claim a full refund of the withheld tax. The return is usually straightforward: you report the income as exempt under the agreement and request your money back. You still file a normal resident return at home.
Reciprocal agreements typically cover only wages and salaries. Other income sourced to the neighboring state — rental income, business profits, gains tied to property there — generally isn’t covered and still triggers a nonresident filing.
Convenience of the Employer Rule for Remote Workers
If you work remotely from home for an employer based in a different state, you might expect to owe tax only where you physically work. A handful of states see it differently. Under the “convenience of the employer” rule, certain states tax nonresident employees based on where the employer’s office is located rather than where the employee actually performs the work.
The rule applies when your remote arrangement exists for your own convenience rather than because the employer requires it. If you could work at the office but choose to work from home in another state, the employer’s state can treat your wages as if you earned them at headquarters. That’s why some remote workers see W-2 withholding for a state they rarely set foot in — and under that state’s law, the withholding is correct.
As of 2026, roughly seven states enforce some version of the rule, with varying aggressiveness. The main escape is the “necessity” exception: if the employer genuinely requires remote work because there’s no office space or the job cannot be done at the main location, the rule generally doesn’t apply. Some states define necessity so narrowly that the exception is almost impossible to satisfy in practice.
Your home state should still offer a credit for the tax the employer’s state withholds, so you won’t pay both in full. But the double filing remains, and if the employer’s state has a higher rate, your total state tax will exceed what a local employer would have cost you.
Local Taxes in Boxes 18, 19, and 20
Some W-2s add another layer below the state lines. Boxes 18, 19, and 20 report local or municipal income taxes: the wages subject to the local tax, the amount withheld, and the name of the locality. If you lived or worked in a city or county with its own income tax, those boxes will show entries.
Local taxes are separate from state taxes and often aren’t covered by state-level reciprocal agreements. A commuter who lives in one state and works in a city in a neighboring state may owe local income tax to that city even if a reciprocal agreement exempts them from the work state’s income tax. Local rates are usually modest, often between 1% and 3%, but they’re an extra filing obligation that’s easy to miss.
If Boxes 19 and 20 show amounts for a locality, check whether that locality requires its own return or whether the local tax is handled through the state return. The answer varies by jurisdiction.
What Happens If You Skip a State Return
States know where you earned income. Employers report W-2 data to both the IRS and the relevant state tax agencies, and the IRS shares return information with states through formal data-exchange programs.4IRS. State Information Sharing If your W-2 sources wages to a state and you never file there, that state will notice eventually.
Penalties for late filing and late payment typically include a flat percentage of the unpaid tax, often 5% to 10%, plus monthly interest that compounds until you pay. Some states add a separate failure-to-file penalty that exceeds the penalty for paying late. Interest on underpayments usually cannot be waived, even with a reasonable excuse.
Even when you believe no tax is owed — because a reciprocal agreement applies or your income falls below the filing threshold — you may still need to file to claim a refund of over-withheld tax or to formally document the exemption. When a state appears in Box 15, filing is the safer move.
Fix Your Withholding for Next Year
If your multi-state situation is going to continue, adjust things now so next spring is easier. Confirm with payroll that the right states are receiving withholding. If a reciprocal agreement applies, get the exemption certificate on file so the work state stops withholding. If the convenience-of-the-employer rule affects you, verify whether your employer is withholding for both states or only one.
Also check that withholding in each state is actually enough to cover your liability there. When income is split between states, neither state’s withholding may be sufficient on its own. If you owed a large balance this year, quarterly estimated payments to the state where you expect a shortfall can keep you out of underpayment penalties next time.