California taxes a Roth conversion as ordinary income. Texas and Florida don’t tax it at all. A federal law from 1996 decides which state gets to ask — and it turns entirely on where you live the day you convert.
Run a Roth conversion through almost any calculator and you get a federal figure. For a household in Texas or Florida, that figure is the whole bill. For one in California, it is roughly three-quarters of it — and the missing quarter is never small.
California gives capital gains no preferential rate, and it gives conversion income none either. A converted dollar is ordinary income at the state’s graduated rates, stacked on top of everything else you report that year. On a large conversion, the top of that stack lands in the state’s upper brackets, which run into the double digits.
| A $500,000 conversion | Texas or Florida | California |
|---|---|---|
| Federal tax | Yes | Yes — identical |
| State tax on the conversion | None | Ordinary rates, into the double digits at the top |
| Preferential rate available? | — | No — California has none |
| Order-of-magnitude difference | — | Tens of thousands, on the same decision |
The number matters, but the interesting part is what governs it. This is not a deduction to hunt for or a form to file. It is a single binary fact about a single day: where you were a resident when the conversion happened.
Before 1996, several states did exactly that. You spent a career in one state, deferred income into a retirement plan, retired somewhere else — and the state where you had earned it billed you when the money came out. California was the most aggressive practitioner, and retirees who had moved to no-tax states complained loudly enough that Congress acted.
The result was the Pension Source Law, codified at 4 U.S.C. § 114. Its operative sentence is one line long: no state may impose an income tax on the retirement income of an individual who is not a resident or domiciliary of that state. The definition of retirement income in the statute covers qualified plans, 401(k)s, 403(b)s, and individual retirement accounts — traditional and Roth alike.
The consequence for conversion planning is direct. A Roth conversion is a distribution event from a retirement account. Only the state you actually reside in on that date can tax it. The state where the money was earned, deducted, and deferred has no claim once you are genuinely gone.
What this is not: a loophole, a shelter, or anything requiring a structure. It is the default rule, written by Congress, and it has been settled law for three decades. The only thing it asks of you is that the move be real.
The statute defers to the old state’s own definition of residency — which means the state you are leaving writes the test you have to pass. California’s is among the most demanding in the country, and it is not a day count you can satisfy with a calendar.
What California examines is domicile: the place you intend as your true, permanent home, evidenced by the whole arrangement of your life. There is no single controlling factor, which is precisely what makes a partial move dangerous. The kinds of things that get weighed:
The failure mode is rarely fraud. It is the incomplete move: the couple who buys in Scottsdale or Naples, spends most of the year there, and keeps the California house, the California doctors, and the California licenses “for now.” They feel moved. On the state’s test they may still be residents — and a seven-figure conversion executed in that window is exactly the event that draws a residency examination years later.
There is also a part-year trap. Move mid-year and you file as a part-year resident, with income allocated between the two states by when it was recognized. A conversion executed in the weeks before the move lands on the wrong side of that line even though the move happened that same year.
Most households in this position are not choosing whether to move. They are already planning it — closer to grandchildren, out of the weather, out of the property tax. The conversion is the thing that has been sitting on the list for a couple of years, waiting for a reason to happen.
Put those two facts in the wrong order and the state tax is simply donated. Put them in the right order and it never arises. The same conversion, the same balance, the same federal bill — and a state line item that goes to zero because it happened in the second year instead of the first.
What makes this genuinely worth planning rather than merely noting is that the low-bracket window and the relocation window are both finite, and they rarely have the same length. Someone retiring at 64 and moving at 67 has three conversion years that are federally cheap and fully taxed by the state, then a stretch that is federally cheap and state-free — and required withdrawals waiting at the end of both. The plan is not “convert” or “move.” It is how much in which year, on which side of the state line.
A detail that catches people: the conversion is taxed in the year it is executed, not the year it is decided. A conversion ordered in late December that settles after January 1 belongs to the new year — which can be the difference between the last California year and the first Texas one. Custodians are busy in late December. Do not let a processing queue pick your state for you.
The strategy is real, but it is not universal, and the cases where it loses are worth naming plainly:
Which column you land in depends on your balance, your bracket, your timeline, your Medicare exposure, and how firm the move actually is. That is a numbers question, and it is answerable — but not by a rule of thumb, and not by a calculator that stops at the federal line.
Yes, if you are a California resident when you convert. California has no preferential rate for this income — the converted amount is added to ordinary income and taxed at the state’s graduated rates, which reach into the double digits on large conversions. Texas and Florida impose no state income tax, so a conversion made as a resident of either is taxed federally only.
No, provided you are genuinely a nonresident when the conversion occurs. Under 4 U.S.C. § 114 — the federal Pension Source Law enacted in 1996 — no state may impose income tax on the retirement income of someone who is not a resident or domiciliary of that state, and the statute covers IRA and qualified plan distributions. A former state cannot reach back for money that was earned there but converted after you left.
There is no waiting period in the statute. What matters is whether you have actually changed residency and domicile under the old state’s rules on the date of the conversion — not how many days have passed. California in particular examines the whole picture: where your home, family, vehicles, doctors, bank accounts, voter registration, and professional licenses are. Converting shortly after a genuine, complete move can be fine; converting after a partial move that leaves substantial ties behind can fail.
When you are moving to another income-tax state rather than a no-tax one; when the move is not genuine or not complete; when the federal cost of delay — higher brackets, Medicare surcharges — outweighs the state saving; and when waiting pushes the conversion past the point where required withdrawals have already filled your brackets. The state question is one input, not the whole decision.
Your brackets, your first RMD, your IRMAA exposure — free, in about 3 minutes. The state half is a conversation.
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