North Carolina and South Carolina do not have a tax reciprocity agreement. If you live in one Carolina and work in the other, you have to file income tax returns in both states. The saving grace is a credit on your resident return for taxes paid to the other state, so the same wages don’t get taxed twice. You’ll do more paperwork than a single-state worker, but your total tax bill lands in roughly the same place.
What No Reciprocity Means for Your Return
In states that have reciprocity agreements, a cross-border commuter only owes income tax to the state where they live. The work state stays out of it. About 16 states and the District of Columbia participate in those arrangements. Neither Carolina does.
Without reciprocity, both states tax the income the way most states do. The work state taxes it as the source of the wages. The home state taxes it because residents owe tax on all income no matter where they earned it. North Carolina imposes its income tax on every nonresident who earns income from a business, trade, profession, or occupation carried on in the state.1North Carolina General Assembly. North Carolina Code 105-153.2 – Purpose of Part; Persons Taxable South Carolina requires the same of nonresidents earning income attributable to work performed or property located in the state.2South Carolina Legislature. South Carolina Code 12-6-1720 – Taxable Income of Nonresidents
Practically, that means two returns. A South Carolina resident working in North Carolina files a North Carolina nonresident return (Form D-400) reporting the NC-source wages, plus a South Carolina resident return reporting all income. A North Carolina resident working in South Carolina files an SC nonresident return (Form SC1040 with Schedule NR) plus a full North Carolina resident return. South Carolina bases its taxable income on the federal Internal Revenue Code, which starts from worldwide income, so residents can’t leave out-of-state wages off the SC return.3South Carolina Legislature. South Carolina Code 12-6-40 – Application of Federal Internal Revenue Code to State Tax Laws
The Credit That Prevents Double Taxation
Filing in both states does not mean paying tax twice on the same dollars. Each Carolina gives its residents a credit for income tax paid to the other state on the same income.
North Carolina residents who paid South Carolina tax on wages earned there can claim a credit against their NC tax. The credit equals the lesser of the tax actually paid to South Carolina or the amount of North Carolina tax attributable to that same income.4North Carolina General Assembly. North Carolina Code 105-153.9 – Tax Credits for Income Taxes Paid to Other States by Individuals To claim it, you attach documentation showing the tax paid to South Carolina along with a copy of the South Carolina return.5North Carolina Department of Revenue. Credit for Income Tax Paid to Another State or Country
South Carolina residents who paid North Carolina tax on wages earned there get a mirrored credit on their SC return for income taxed by both states.6South Carolina Legislature. South Carolina Code 12-6-3400 – Credit for Income Tax Paid by South Carolina Resident to Another State The same limit applies: the credit cannot exceed the South Carolina tax on that income.
The cap matters. Because the credit is limited to your home state’s tax on the cross-border income, the higher-rate state controls your total bill. If the work state’s rate is higher, the credit wipes out your home-state liability on that income and you effectively pay the work state’s rate. If the work state’s rate is lower, the credit partially offsets your home-state tax and you effectively pay the home state’s rate. You never pay both rates stacked.
How the Rate Difference Plays Out
Predicting your outcome comes down to which state has the higher effective rate on your income.
North Carolina uses a flat income tax rate of 3.99% for taxable years beginning after 2025.7North Carolina Department of Revenue. Tax Rate Schedules Every dollar of North Carolina taxable income is taxed at the same rate.
South Carolina uses a graduated structure. The first $3,200 of taxable income is taxed at 0%, income between $3,200 and $16,040 at 3%, and income above $16,040 at the top marginal rate. That top rate started at 6.5% in 2022 and is being phased down by one-tenth of a percent per year toward a floor of 6%, contingent on state revenue growth meeting certain thresholds.8South Carolina Legislature. South Carolina Code 12-6-510 – Tax Rates for Individuals, Estates, and Trusts The brackets adjust annually for inflation.9South Carolina Legislature. South Carolina Code 12-6-520 – Annual Adjustments to Income Tax Brackets
For most cross-border workers earning above the top-bracket threshold, South Carolina’s effective rate is higher than North Carolina’s 3.99%. A North Carolina resident working in South Carolina will typically pay SC tax at the higher rate, and the NC credit (capped at the NC tax on that income) leaves no additional NC balance on those wages. Effectively, you pay South Carolina’s rate.
Reverse the commute and the numbers reverse too. A South Carolina resident working in North Carolina pays the lower NC rate up front, then owes South Carolina the difference between the SC rate and the NC credit. Effectively, you pay South Carolina’s rate on that income anyway, just split between two checks.
Withholding: What Comes Out of Your Paycheck
Your employer in the work state withholds that state’s income tax. A South Carolina resident with an NC employer sees NC withholding. A North Carolina resident with an SC employer sees SC withholding. Nothing is being withheld for your home state during the year.
That leaves a potential gap. If the home state’s rate on your cross-border income exceeds the work state’s, you’ll owe a balance when you file. Two options close the gap. Ask your employer whether they can withhold additional tax for your home state, since some multistate employers are set up to do this. Otherwise, make estimated quarterly tax payments to your home state to cover the difference. Running the numbers early in the year is easier than facing a lump sum in April.
Filing Order and Documentation
File the nonresident return in the work state first. You need the actual tax paid figure from that return to calculate your credit on the home-state return. Filing the home-state return first and estimating the credit invites a mismatch that can trigger a notice or an amended return later.
Keep your records organized. North Carolina requires you to attach receipts showing the tax paid to the other state and a copy of the return you filed there when claiming the credit.4North Carolina General Assembly. North Carolina Code 105-153.9 – Tax Credits for Income Taxes Paid to Other States by Individuals Even where e-filing accepts a return without attachments, keep the documentation in case the state follows up.
If You Moved or Work From Home
Moving between the two states during the year puts you in part-year resident status in each. Part-year filers report income earned while living in each state to that state and follow separate allocation instructions on the respective forms; the credit rules for pure commuters don’t map directly onto that situation.
Remote workers should watch physical location, not employer location. Neither Carolina uses a “convenience of the employer” rule (the approach a few northeastern states use to tax remote workers by where the employer sits). If you live in one Carolina and sometimes work from home for an employer in the other, generally only the days you physically cross the border count as work-state income. Track those days, especially if your employer isn’t splitting withholding between the two states for you.