Roth Conversion Calculator

The converted amount is added to your ordinary income for the year and taxed at your marginal rates. The cost depends on where the conversion lands in the brackets: a married couple with $40,000 of other income converting $50,000 in 2026 pays about $5,660 of federal tax, an 11.3% effective rate, because most of the conversion fills the 10% and 12% brackets. The same conversion on top of a high salary could cost 32% or more. This calculator computes the exact incremental tax at 2026 brackets, including any state tax and any extra Social Security taxation the conversion triggers.

A Roth conversion moves money from a pre-tax account (traditional IRA, 401(k), 403(b)) into a Roth IRA. You pay ordinary income tax on the converted amount now; in exchange, the money grows tax-free, qualified withdrawals are tax-free, and Roth IRAs have no required minimum distributions during your lifetime. There is no income limit and no dollar limit on conversions, which is also why the backdoor Roth strategy works.

The classic window is a low-income year: the gap between retiring and starting Social Security or RMDs, a sabbatical, or an early-retirement year before pension income begins. Converting when your marginal rate is temporarily low locks in that low rate on money that would otherwise be taxed at a higher rate later. Market downturns are a secondary opportunity, since converting depressed shares moves more future recovery into the tax-free side. Conversions count in the calendar year they're made, so the deadline is December 31, not tax day.

Bracket-filling means converting just enough to use up the room left in your current bracket without spilling into the next one. If a couple's taxable income is $7,800, they have $17,000 of room left in the 10% bracket and another $76,000 of 12% room above that. Converting to the top of a low bracket each year, rather than one huge conversion in a single year, usually produces a lower lifetime tax bill. The calculator's fill table shows the room and cost for each bracket from your position.

Yes, and it's the cost most conversion calculators miss. How much of your Social Security is taxed depends on provisional income, which the conversion raises. A conversion can drag benefit dollars from untaxed to taxable, so the true cost of converting is the bracket tax plus the extra tax on your benefits. In some ranges each converted dollar brings $0.85 of benefits into taxation with it, making the effective rate much higher than your bracket suggests. This calculator runs the IRS worksheet with and without the conversion and shows the difference.

Each conversion starts its own 5-year clock. Withdrawing converted principal before that clock runs and before age 59½ triggers a 10% penalty on the withdrawal. After 59½ the penalty clock stops mattering for conversions, though a separate 5-year rule governs whether earnings are tax-free. For early retirees this is a feature, not a bug: a Roth conversion ladder converts a slice each year so that five years later a steady stream of penalty-free money comes available.

They can. Medicare's IRMAA surcharges are based on your income from two years earlier, so a large conversion at 63 or later can raise your Part B and Part D premiums two years down the road. The thresholds are cliffs, not phase-ins: one dollar over a line raises the premium for the whole year. If you're within a few years of Medicare, check the current IRMAA thresholds before settling on a conversion size.

No. Recharacterization of conversions was repealed by the Tax Cuts and Jobs Act, so conversions made in 2018 or later are permanent. That makes sizing the conversion correctly before year-end the whole game: convert an amount you're confident about, and remember you can always convert more next year, but you can never convert less this year after the fact.