Live in NH, Work in MA: Tax Calculator

Why your household's other income matters

The day count settles how much of your salary Massachusetts can tax, and nothing else changes it. What the rest of your household's income changes is the deduction side. A nonresident gets the same personal exemption as anyone else, $4,400 single or $8,800 on a joint return in 2025, but only the Massachusetts fraction of it: the exemption is prorated by the share of your total income that came from Massachusetts.

So a spouse earning in New Hampshire, a retirement withdrawal, or a second job all make that share smaller, which shrinks the exemption and raises the Massachusetts tax slightly. It usually moves the answer by tens of dollars rather than hundreds, and it is one of the places software and DIY filers get it wrong in both directions. That is why the calculator asks.

How an overpayment gets claimed back

If your W-2 shows your full salary as Massachusetts wages, the claim happens on your Massachusetts nonresident return: the day-count wages go on line 5, the full withholding from box 17 goes on the withholding line, and the difference is claimed as a refund. The return can be e-filed, which gets a refund back faster than mailing it on paper.

For a year you already filed without the day count, the same correction goes on an amended Massachusetts return. Massachusetts accepts one within three years of the date you filed the original return, two years from an assessment, or one year from a payment, whichever is later, so up to three back years are usually still open. The calculator's year menu goes back that far for exactly this reason.

What backs up the day count

If Massachusetts asks, the burden of supporting the fraction is on you. Your employer's records carry the most weight: a badge or building-access report lists the exact dates you were in the Massachusetts office, and timekeeping data and a written hybrid schedule support it. Your own calendar, kept as the year goes, comes next, then commuting charges and parking records for the days in question. Many employers purge access logs after a year, so ask for a copy in the middle of the year and another one in January, and keep whatever you used to build the count.

Fixing the withholding going forward

Claiming it back on the return means lending Massachusetts money all year. The forward fix is asking payroll to withhold Massachusetts tax on your in-state share instead of the full salary. Take-home pay goes up right away. The trade-off is that the estimate has to hold: change to a schedule with more office days, or land a project that keeps you in Massachusetts for a stretch, and the lighter withholding leaves a balance due at filing.

What this estimate includes, and what it leaves out

The calculator follows the Massachusetts nonresident return in order: the working-day denominator with holidays and leave removed, the Massachusetts share of your wages, the Social Security and Medicare deduction on that Massachusetts income, and the personal exemption prorated by your household's Massachusetts share. The flat 5% rate applies to what is left. When you leave box 17 blank, it assumes your employer withheld on the full salary, which is the common case this page exists for.

Some of the return is still outside it. Dependent exemptions, the low-income provisions for smaller Massachusetts incomes, the rental and commuter deductions, and the extra 4% surtax on income over roughly $1.1 million are all left out, and income taxed at rates other than the wage rate is outside it too. Treat the result as the number that tells you whether a claim is worth pursuing, and have the actual return prepared from your real records.