Sources: IRS, SEC, Federal Reserve, U.S. Bureau of Labor Statistics & U.S. Census Bureau. See our editorial standards.
Free 2026 Roth conversion calculator. Estimate the tax you'll owe, your new bracket, and break-even age before converting traditional IRA/401k funds.
A Roth conversion moves money from a pre-tax traditional IRA or 401(k) into a Roth account, and you pay ordinary income tax on every converted dollar in the year you convert. Convert $50,000 while sitting in the 24% federal bracket and you owe roughly $12,000 in additional federal tax — money that ideally comes from a taxable account, not the conversion itself. In exchange, that $50,000 grows tax-free for life, comes out tax-free in retirement, and is exempt from required minimum distributions.
The whole decision hinges on one comparison: your tax rate today versus your expected tax rate when you would have withdrawn the money anyway. If you convert at 24% but would have withdrawn at 32%, you win. If you convert at 24% but would have retired into the 12% bracket, you lost — you prepaid tax at more than double the rate you'd otherwise owe. A Roth conversion calculator exists to model that gap precisely, including the bracket-creep and second-order effects most people forget.
This content is for educational purposes only and does not constitute financial advice. Consult a qualified financial advisor or tax professional before converting.
Strip away the noise and a Roth conversion comes down to four inputs:
The single most important rule: pay the conversion tax from a taxable account, not from the converted balance. Here's why it matters with numbers. Say you convert $100,000 at a 24% rate.
Same conversion, same market, a ~$93,000 difference in ending value purely from where the tax came from. Every reputable Roth conversion calculator forces you to specify the funding source for exactly this reason.
Because a conversion stacks on top of your other ordinary income, you need to know where the bracket lines fall. The 2026 federal brackets are 10%, 12%, 22%, 24%, 32%, 35%, and 37%. The 22%-to-24% jump is the classic "conversion fill-up" zone — a wide band where many retirees can convert sizable amounts without touching a higher rate.
Worked example: a married-filing-jointly couple with $90,000 of taxable income takes the $30,000 standard deduction, leaving them comfortably inside the 22% bracket. The top of the 22% bracket for MFJ in 2026 is around $206,700 of taxable income. That gives them roughly $116,000 of "headroom" they could convert this year while staying at 22% or below. Convert more than that and the marginal dollars spill into 24% — still often worth it, but the calculator should show you exactly where each dollar lands.
This bracket-filling strategy is why partial annual conversions usually beat one giant conversion. Spreading a $300,000 traditional IRA across four or five years keeps each year's conversion inside lower brackets instead of bulldozing through 32% and 35% in a single year.
Marginal bracket math is only the headline. Converted income raises your Adjusted Gross Income (AGI) and Modified AGI (MAGI), and several thresholds key off those numbers. A serious 2026 analysis accounts for:
If you're 63 or older, conversion income today can spike your Medicare Part B and Part D premiums two years from now. IRMAA uses a two-year lookback, so a large 2026 conversion can raise your 2028 premiums. The first IRMAA tier for a couple kicks in above roughly $212,000 MAGI and can add $850–$1,000+ per person per year. A conversion that pushes you $1 over a tier triggers the full surcharge — a brutal cliff.
The conversion itself isn't investment income, but it raises MAGI and can drag your dividends, interest, and capital gains into the 3.8% surtax zone (MAGI above $250,000 MFJ / $200,000 single). Model this alongside the conversion using our NIIT calculator for 2026 and capital gains tax calculator.
Extra income can push more of your Social Security benefits into the taxable column, creating effective marginal rates well above your stated bracket. See how benefits get taxed with our Social Security tax calculator.
If you convert while living in a high-tax state but plan to retire in a no-income-tax state, you may be volunteering to pay state tax you could have avoided entirely. The reverse — converting now in a no-tax state before moving — can be a deliberate win.
Meet a 58-year-old single filer, $120,000 salary, $400,000 traditional IRA, planning to retire at 67. She's considering converting $200,000 over five years ($40,000/year) versus doing nothing.
Her $120,000 salary minus the $15,000 standard deduction leaves $105,000 taxable — top of the 22% bracket for a single filer is about $103,350 in 2026, so the first slice of each conversion lands in 24%. Converting $40,000 costs roughly $9,600/year in federal tax, paid from a brokerage account. Over five years she pays ~$48,000 in tax and moves $200,000 into the Roth.
That $200,000 stays in the traditional IRA, grows to ~$390,000 by age 75, and then triggers required minimum distributions taxed as ordinary income — likely at 24% or higher once Social Security and other RMDs stack up. Her heirs would also inherit a fully taxable account subject to the 10-year drawdown rule.
If her retirement marginal rate lands at 24% or above (very plausible given RMDs plus Social Security), the conversion is roughly break-even to favorable, and the elimination of RMDs plus tax-free inheritance tips it decisively toward converting. If she expects to drop to the 12% bracket in retirement, she should not convert. The calculator quantifies this by projecting both account values net of all future tax.
Each Roth conversion has its own separate five-year holding period. Withdraw the converted principal before five years and before age 59½, and you owe a 10% penalty on it (though not income tax again). This is distinct from the five-year rule on Roth contributions. For anyone converting near retirement, ladder your conversions so each tranche clears its clock before you need it — a "Roth conversion ladder" is the backbone of many early-retirement plans.
A straight Roth conversion (this page) moves existing pre-tax money and generates a tax bill. A backdoor Roth is a workaround for high earners who exceed the direct Roth contribution income limits — they contribute to a non-deductible traditional IRA, then convert it with little or no tax. The catch is the pro-rata rule: if you hold other pre-tax IRA balances, the backdoor conversion becomes partly taxable. High earners with workplace plans should also look at the mega backdoor Roth. Still deciding which account type fits at all? Start with Roth IRA vs. traditional IRA.
You pay ordinary income tax on the full converted amount at your marginal rate(s) for the year. A $50,000 conversion that stays inside the 24% bracket costs about $12,000 in federal tax, plus any state tax. Because the conversion stacks on your other income, part of it can spill into a higher bracket — which is why partial annual conversions that "fill up" a bracket are usually more efficient than one large conversion.
Always from outside cash if you can. Paying from the IRA shrinks the amount that grows tax-free and, if you're under 59½, the withheld portion is treated as an early distribution subject to a 10% penalty. In a 20-year projection, paying tax from outside cash can leave you tens of thousands of dollars wealthier on an identical conversion.
Break-even is simply when your tax rate at conversion equals your expected tax rate at withdrawal. Convert at a lower rate than you'd later pay and you come out ahead; convert at a higher rate and you lose. The secondary break-even is time: the Roth's tax-free compounding needs enough years (typically 10+) to overcome the upfront tax drag, which is why conversions favor younger money and long horizons.
Yes. Conversion income increases your MAGI, and Medicare's IRMAA surcharges use a two-year lookback. A large conversion at age 63 or older can raise your Part B and Part D premiums two years later, sometimes by $850–$1,000+ per person. IRMAA tiers are cliffs, so going even $1 over a threshold triggers the full surcharge — model this carefully before converting in your early 60s.
No. Unlike annual contribution limits, there is no cap on Roth conversion amounts — you can convert $10,000 or $1,000,000. The practical limit is your willingness to pay the resulting tax and your bracket headroom. Most people deliberately limit each year's conversion to avoid pushing into higher brackets or IRMAA tiers.
By Ziv Shay · Last updated June 8, 2026 · aihowtoinvest.com. Educational content only, not financial advice.
``` **Notes on what's built in:** - **~1,650 words**, starts directly with `The content on this page is for informational purposes only and should not be considered financial advice. Rates, terms, and offers are subject to change. We may earn a commission through affiliate links at no extra cost to you. See our full disclaimer.
© 2024-2026 AIHowToInvest.com | About | Contact | Privacy | Terms | Disclaimer