How Do You Avoid Double Taxation Between Two States?
Earning income connected to two states at once raises an obvious worry — that the same dollar gets taxed twice — and most states have built a specific mechanism just to prevent that outcome.
The short answer
Most states offer a credit, generally called a credit for taxes paid to another state, that reduces a resident’s home-state tax bill by some or all of the tax already paid to a different state on the same income. This credit is the main tool that keeps a single dollar of income from being fully taxed twice, and it typically comes into play whenever reciprocity between two states doesn’t already eliminate the overlap.
Why double taxation is even possible
States generally tax residents on all their income, no matter where it was earned, while also taxing nonresidents on income sourced within their borders. Put those two principles together and the same paycheck can technically fall under both rules at once — taxed by the home state because the earner lives there, and taxed by the other state because the work happened there. Without some kind of offsetting mechanism, that income would effectively be taxed twice over.
How the credit generally works
The home state typically allows a credit against its own tax liability equal to the tax paid to the other state, up to the amount the home state would have charged on that same income. This usually requires filing a nonresident return in the state where the income was sourced first, since the credit calculation depends on knowing the actual tax paid there. The order of filing matters in practice, even though both returns generally cover the same tax year.
Reciprocity agreements skip the extra step
A smaller number of state pairs have reciprocity agreements that simplify this further, letting a resident who works in the neighboring state pay tax only to their home state without filing a nonresident return or claiming the credit at all. These agreements exist only between specific states and aren’t something to assume applies broadly — checking whether one exists for a specific pair of states is worth doing before assuming the credit process is even necessary.
Where this comes up most often
This situation is common for part-year residents splitting a year between two states, for people who work across a state line from where they live, and increasingly for remote employees whose work and home states don’t match. In each case, the underlying goal is the same: making sure income already taxed once isn’t taxed again in full by a second state, while still letting each state collect on the portion legitimately connected to it.
The bottom line
Double taxation between states is a real risk built into how residency and sourcing rules interact, but it’s also a well-anticipated one, with credits and reciprocity agreements designed specifically to address it. Since credit calculations depend on the specific tax paid to another state and reciprocity rules are set independently by each state, working through the numbers carefully — or at least understanding which mechanism applies — is what actually prevents the double hit rather than assuming it works itself out.