Free tool · No sign-up
How much can I convert to Roth before the next bracket or IRMAA tier?
Find how much you could convert to a Roth in 2026 before your next dollar lands in a higher federal bracket or pushes you into a Medicare surcharge tier, and what the conversion would cost in tax.
Yearfold is a financial-education tool. It is not a registered investment adviser and does not provide personalized investment, tax, or legal advice. Results are probabilistic projections based on historical data and stated assumptions; they are not guarantees. Methodology
By Mindaugas Laucius · Last reviewed October 21, 2026
Room before the next limit
$29,000
The next Medicare IRMAA tier comes first.
Federal tax on a $29,000 conversion
$6,763
23.3% of the amount converted
- Deductions: $23,850; taxable income before converting: $56,150 (22% bracket).
- Room in the 22% bracket: $48,490 before 24%.
- Room before the next IRMAA tier: $29,000.
Federal estimate only; doesn’t model how added income can make more Social Security taxable. See Roth conversion ladders for the multi-year view.
How this works
A Roth conversion moves money from a traditional IRA or 401(k) into a Roth account. The converted amount counts as ordinary income this year, and after that the money grows tax-free. The planning question is usually how much to convert before the next dollar gets taxed at a higher rate.
We start from your income before the conversion, subtract the 2026 standard deduction ($16,100 single, $32,200 joint), the extra $2,050 (single) or $1,650 (each married spouse) for being 65 or older, and the new senior deduction of up to $6,000 per person 65+. That senior deduction shrinks by 6% of income above $75,000 single or $150,000 joint, so inside the phase-out each converted dollar raises taxable income by $1.06. That's why the effective tax rate on a conversion can exceed your bracket.
From 63 on, a second limit applies. Medicare's IRMAA surcharge is based on income two years earlier, so a conversion at 63 can raise your premiums at 65. The tool shows the room before the next IRMAA tier and reports whichever limit, bracket or IRMAA, you would hit first.
Worked example: Single, age 66, $80,000 of income before converting
- Deductions: $16,100 standard + $2,050 age-65 addition + senior deduction $6,000 − 6% × ($80,000 − $75,000) = $5,700. Total $23,850.
- Taxable income: $80,000 − $23,850 = $56,150, inside the 22% bracket, which runs to $107,550.
- Bracket room: each converted dollar adds $1.06 of taxable income here, so ($107,550 − $56,150) ÷ 1.06 ≈ $48,490.
- IRMAA room: the first tier begins at $109,001, so $109,000 − $80,000 = $29,000.
IRMAA binds first: a conversion of up to $29,000 stays under both limits. Federal tax on $29,000 is about $6,763, an effective 23.3%, which is 22% times the $1.06 of taxable income each dollar adds.
The full method behind every Yearfold number is on the methodology page.
Sources
- IRS Rev. Proc. 2025-32 — 2026 brackets and deductions
- IRS — enhanced deduction for seniors
- CMS — 2026 Medicare Part B premiums and deductibles
Rules verified against these sources on October 21, 2026.
Questions
Why is the tax on my conversion more than my bracket rate?
If your income sits in the senior-deduction phase-out ($75,000 to $175,000 single, $150,000 to $250,000 joint, for each person 65+), every converted dollar also removes 6 cents of deduction. The conversion is then taxed at your bracket rate times 1.06.
Does a Roth conversion affect Social Security taxes?
It can. Up to 85% of Social Security benefits become taxable as other income rises, which this tool doesn't model separately. Enter your income before conversion including the taxable part of your benefits.
What about state income tax?
Pick your state for a rough estimate. Most states tax conversions as ordinary income; a few with no income tax don't, and some exempt retirement income only when it's distributed, not converted. Check your state guide for the details.
Is converting up to the top of my bracket always worth it?
Not always. It depends on your tax rate later, when you'd otherwise withdraw the money or face larger RMDs, your heirs' tax rates, and whether you can pay the tax from outside the IRA. This tool shows the room and the cost; the decision is yours.
How long do the senior deduction and these brackets last?
The $6,000 senior deduction applies for tax years 2025 through 2028 under current law. The brackets and standard deduction are indexed each year; the figures here are the IRS's 2026 amounts.
See this in your full plan
The free 10,000-path calculator puts this answer next to everything else: savings, spending, Social Security, taxes, Medicare and a spouse, with the odds your money lasts. Your inputs from this tool carry over.
See this in your full planRelated free tools
- IRMAA calculatorWill I pay a Medicare surcharge, and can I appeal it?
- RMD calculatorHow much must I withdraw for my RMD, and by when?
- Health insurance before 65What will health insurance cost until Medicare at 65?