≈ $14,770 federal tax Converting $100,000 as a married filing jointly in 2026 (with about $60,000 of other ordinary income) adds roughly $14,770 in federal income tax — an effective rate of 14.8% on the converted amount. State tax is additional.
How the $100,000 conversion is taxed
A Roth conversion adds the converted amount to your ordinary income for the year. We model a married filing jointly who already has about $60,000 of other taxable income (wages, pension, interest, or earlier withdrawals) before the conversion. After the 2026 standard deduction of $31,500, taxable income rises from $28,500 to $128,500. Because the conversion stacks on top, its first dollars are taxed at your current marginal rate and its last dollars at the highest bracket it reaches.
| Item | Before conversion | After $100,000 conversion |
|---|---|---|
| Other ordinary income | $60,000 | $60,000 |
| Roth conversion added | $0 | $100,000 |
| 2026 standard deduction | −$31,500 | −$31,500 |
| Taxable income | $28,500 | $128,500 |
| Federal tax owed | $2,924 | $17,694 |
| Extra federal tax from the conversion | $14,770 (14.8% of $100,000) | |
Marginal vs effective: Your conversion spans the 12%–22% brackets. The headline 14.8% effective rate is lower than the 22% top marginal rate because only the final dollars are taxed at the top. If you want to keep the whole conversion inside one bracket, convert a smaller amount — the calculator below shows the bracket ceiling for your exact income.
Two side effects bigger than the income tax
IRMAA — the Medicare premium surcharge
The conversion lifts MAGI to about $160,000. That stays under the 2026 first IRMAA tier ($218,000 for a married filing jointly), so no Medicare surcharge is triggered at this level. See the RMD + IRMAA calculator for the lookback timeline.
ACA premium tax credits
If you buy coverage on the Marketplace, the same MAGI determines your subsidy. At $160,000, you are over the 400% federal-poverty-level cliff ($81,760 for this household), so a conversion this size eliminates the premium tax credit. Either convert after you start Medicare, or keep the conversion under the cliff. The ACA Subsidy Cliff Optimizer finds the largest conversion that keeps your credit.
Should you convert $100,000 this year?
- Fill the bracket, don't overflow it. Convert up to the top of your target bracket. For this baseline that means watching the 22% threshold.
- Mind the two cliffs. IRMAA (two-year lookback) and the ACA 400% FPL cliff can each cost more than the income tax itself. Both are flagged above for this scenario.
- Spread large balances over several low-income years rather than one big conversion, unless you have a genuine zero-income gap year.
- Add state tax. A $100,000 conversion in a high-tax state can add several thousand dollars more. Compare states on the state retirement tax calculator.
Model the full multi-year conversion ladder
Free 10,000-path Monte Carlo: bracket-fill optimizer, IRMAA lookback, ACA cliff, and state tax — all in your browser, no signup.
Open the Roth optimizer →Other conversion amounts (married filing jointly)
- $10,000 conversion (married filing jointly)
- $25,000 conversion (married filing jointly)
- $50,000 conversion (married filing jointly)
- $75,000 conversion (married filing jointly)
- $150,000 conversion (married filing jointly)
- $200,000 conversion (married filing jointly)
Or switch filing status: $100,000 for single filers.
FAQ
How much tax will I pay on a $100,000 Roth conversion in 2026?
For a married filing jointly with about $60,000 of other ordinary income, converting $100,000 adds roughly $14,770 in federal income tax — an effective rate of about 14.8% on the converted amount. The conversion is stacked on top of your existing income, so the first dollars are taxed at your starting marginal rate (12%) and the last dollars at 22%. State income tax (if any) is on top of this.
Is a Roth conversion taxed as ordinary income or capital gains?
The full pre-tax amount you convert is taxed as ordinary income in the year of the conversion — not at the lower long-term capital-gains rates. That is why timing the conversion into a low-income year (early retirement, a gap year, or a sabbatical) is the core of conversion-ladder strategy.
Will a $100,000 conversion trigger an IRMAA Medicare surcharge?
With this baseline, the conversion pushes MAGI to about $160,000, which stays under the 2026 first IRMAA tier ($218,000 for married filing jointlys), so no Medicare surcharge is triggered at this income level. Larger conversions or higher base income can change that.
Does a Roth conversion affect ACA Marketplace subsidies?
Yes. The conversion raises MAGI, and ACA premium tax credits phase down as MAGI rises. At this baseline, MAGI of $160,000 is above the 400% federal-poverty-level cliff ($81,760 for this household size), so you would lose premium tax credits if you are on a Marketplace plan. Convert before Medicare or keep the conversion under the cliff if subsidies matter.
Can I undo a Roth conversion if I convert too much?
No. Since the 2017 Tax Cuts and Jobs Act, Roth conversions are irrevocable — recharacterization back to a traditional IRA is no longer allowed. That makes the fill-the-bracket approach important: convert only up to the top of your target bracket so you never owe more than you planned.
Last updated 2026-06-02. Federal brackets are 2026 OBBBA inflation-indexed values; the standard deduction is $31,500 (married filing jointly). Worked example assumes $60,000 of other ordinary income — your real numbers may differ; use the calculator above. Educational only, not tax advice.