Yes, in most states. A Roth conversion is ordinary income in the year you convert, and 41 states plus Washington, D.C. tax ordinary income. The federal bill is usually the larger number, but state tax can move a conversion decision by thousands of dollars per year, and it is the piece most national calculators ignore.
The three groups
No state tax on conversions. Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, and Wyoming have no income tax at all. Washington taxes only large long-term capital gains, and a conversion is not a capital gain, so it owes nothing there either. If you live in one of these nine states, your conversion decision is purely federal: brackets, IRMAA, and Social Security interaction.
Flat-rate states. States like Illinois, Colorado, Pennsylvania, and Indiana apply one rate to your whole taxable income. The state cost of a conversion is close to rate times amount, with one important exception: several flat states exempt retirement income or IRA distributions entirely, which can make a conversion far cheaper than the headline rate suggests. Illinois excludes IRA distributions regardless of age, Pennsylvania excludes them from age 60, and Iowa exempts all retirement income from age 55 (Iowa Code 422.7(31)), so a conversion at 66 can cost nothing at the state level despite the flat tax. Mississippi does the same for qualified retirement income at any age.
Graduated-rate states. California, New York, New Jersey, Minnesota, Hawaii and most others use brackets, so a large conversion can climb into higher state brackets the same way it climbs federal ones. California’s top rate reaches 13.3%. In these states, spreading conversions across more years matters twice: once for the federal brackets and again for the state ones.
The same conversion, fifty-one ways
The state conversion-tax study runs one scenario through every jurisdiction’s 2026 rules: a single filer, age 66, converting $100,000 on top of $80,000 of other income. Selected rows, all computed by the same functions as the calculator:
| State | State tax on the conversion | Effective rate |
|---|---|---|
| California | $9,300 | 9.30% |
| Oregon | $9,278 | 9.28% |
| Connecticut | $8,180 | 8.18% |
| Minnesota | $7,380 | 7.38% |
| New York | $5,707 | 5.71% |
| Alabama | $5,000 | 5.00% |
| Colorado (flat 4.4%) | $4,400 | 4.40% |
| Arizona (flat 2.5%) | $2,500 | 2.50% |
| Illinois, Iowa, Mississippi, Pennsylvania | $0 | 0% |
| Texas and the 8 other no-tax states | $0 | 0% |
Three things the full table shows that summaries miss. First, the zero row is bigger than the no-tax states: thirteen of fifty-one jurisdictions charge nothing on this example, because retirement-income exclusions in Illinois, Iowa, Mississippi, and Pennsylvania absorb the entire conversion at age 66. A retiree comparing Illinois (4.95% flat rate) against Texas (no income tax) is comparing $0 against $0 for conversion purposes.
Second, income-conditioned exclusions can push a state’s effective rate past its own top bracket. Connecticut deducts IRA and pension income in full below $75,000 of AGI, phasing to zero at $100,000 ($150,000 joint, per CGS §12-701(a)(20)(B)). The $100,000 conversion drags AGI to $180,000, which is taxed itself and also revokes the deduction on the $80,000 of base income: $8,180 of tax, an 8.18% effective rate against a 6.99% top statutory rate, and $8,400 (8.40%) filed jointly. Alabama works the other way: its exclusion for 65+ is capped at $6,000 of defined-contribution distributions (Act 2022-297), so a large conversion pays a flat-looking 5.00% no matter how the small exclusion lands.
Third, rankings flip by filing status: the same conversion filed jointly costs $8,750 in Oregon but $7,085 in California, because Oregon’s brackets compress faster for couples. The full ranked table with CSV covers all fifty-one.
What this changes about bracket filling
State tax does not change the logic of bracket filling, it changes the arithmetic. The conversion amount that exactly fills your federal 22% bracket is the same in Texas and California, but the all-in marginal rate on that conversion differs by up to 13 points. Two planning consequences:
- Age thresholds are cliffs worth waiting for. In Pennsylvania (60) and Iowa (55), converting a year before the exclusion age pays the flat rate on the whole conversion; a year later pays $0. No federal consideration in the conversion window is that binary.
- Moves reprice every remaining conversion year. If a move from a 9.3% state to a 0% state is plausible before your RMDs begin, the state column, $9,300 per $100,000 in the study scenario, is often the deciding factor on whether to convert now or after the move.
Every state page on this site shows the computed state tax on a $50,000 conversion at three income levels, using the same functions as the calculator. Start with your state: California, New York, Texas, Florida, Illinois, or Pennsylvania.