Multi-state income sourcing for remote workers

Remote work broke the oldest assumption in state taxation: that where you work and where you live are the same place. When they aren't, two states can each write rules claiming a piece of the same paycheck — and those rules were not designed to fit together neatly. Understanding the three mechanisms that decide the outcome — sourcing rules, resident credits, and apportionment — is the difference between a clean two-state return and years of amended filings, double tax, or an audit letter from a state you haven't set foot in.

Two claims on the same paycheck

Every state with an income tax asserts two separate rights. As your state of residence, it taxes ALL of your income, wherever earned — that's residence-based taxation. As the state where work is physically performed, it taxes income sourced within its borders even if you live elsewhere — that's source-based taxation. A remote worker living in New Jersey and employed by a Manhattan company triggers both claims at once. The system's pressure-release valve is the resident credit: your home state gives you a credit for taxes properly paid to the source state, so in theory you pay the higher of the two rates, not the sum. In practice, 'properly paid' is where the fights start.

The convenience of the employer rule

Most states source wages to where the work is physically performed. A handful — most famously New York — apply a 'convenience of the employer' rule: if your employer is based there and you work remotely for your own convenience rather than because the employer requires it, your remote days are sourced to the employer's state anyway. Work from your Vermont cabin for a New York firm because you prefer it? New York treats those days as New York days. Only if the employer requires you to work outside the state — a bona fide business necessity, like a role that must be near a client site — do those days escape.

Resident credits: how the offset actually computes

The credit for taxes paid to another state is capped at what your home state would have charged on that same income. If the source state's rate is higher, you eat the difference; if it's lower, you pay your home state the shortfall. The credit is computed income-by-income category on most returns, requires attaching the other state's return, and never refunds excess — it only offsets.

Apportionment: counting your days

When no convenience rule applies, nonresident wages are apportioned by workday ratio: days physically worked in the state divided by total working days, multiplied by total compensation. The burden of proof is on you, and states auditing these returns ask for evidence with dates — badge swipes, calendar entries, cell phone location records, credit card transactions. A vague 'I was mostly home' loses to a state's presumption every time.

1. Count total working days for the year: roughly 260 weekdays minus holidays, vacation, and sick days (typically 230-240).
2. Count days physically worked in the nonresident state — partial days generally count as full days in aggressive states like New York.
3. Divide to get the apportionment percentage, and apply it to total wages, bonuses, and (with lookback rules) equity compensation vesting during the year.
4. Keep contemporaneous evidence: a simple daily log with location, backed by at least one third-party record per week, survives audit far better than a reconstruction.

Reciprocity: the easy cases

• Some neighboring states signed reciprocity agreements that override all of this for wages: you pay only your home state, file one return, and give your employer an exemption certificate so withholding goes to the right place. These pacts cluster in the Midwest and Mid-Atlantic.
• Pennsylvania has reciprocity with New Jersey, Maryland, Virginia, West Virginia, Ohio, and Indiana.
• Illinois pairs with Iowa, Kentucky, Michigan, and Wisconsin.
• Virginia, Maryland, and DC form a three-way pact — crucial for the capital region's commuters.
• Reciprocity covers wages only: business income, rental income, and equity sales still follow normal sourcing rules.

Scenarios that trip people

• The mid-year mover who forgets part-year returns: both states tax you as a resident for their portion of the year, and income must be split by date earned, not just W-2 totals.
• The 'digital nomad' who works a few weeks from a third state: several states assert taxing rights after as little as one working day, though many have 30-day safe harbors — check before an extended stay.
• Equity compensation: RSUs vesting today are often sourced by where you worked during the entire vesting period, so a New York job you left three years ago can still claim a slice of this year's vest.
• The employer who never registered in your state: payroll may refuse to withhold for your home state, leaving you to make estimated payments yourself — the tax is still owed even if nothing was withheld.

The bottom line

Multi-state taxation runs on three gears: source states claim days worked there (or, under convenience rules, days worked anywhere for their employers), home states claim everything but credit taxes properly paid elsewhere, and reciprocity occasionally switches the whole machine off. Your job is to know which gear your situation engages, point your withholding at the right state on day one, and keep a day-count log that would survive a skeptical auditor. Do those three things and a two-state life costs you the higher of two rates — skip them and it can cost you both.