≈ $1,200 federal tax Converting $10,000 as a single filer in 2026 (with about $40,000 of other ordinary income) adds roughly $1,200 in federal income tax — an effective rate of 12.0% on the converted amount. State tax is additional.
How the $10,000 conversion is taxed
A Roth conversion adds the converted amount to your ordinary income for the year. We model a single filer who already has about $40,000 of other taxable income (wages, pension, interest, or earlier withdrawals) before the conversion. After the 2026 standard deduction of $15,750, taxable income rises from $24,250 to $34,250. 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 $10,000 conversion |
|---|---|---|
| Other ordinary income | $40,000 | $40,000 |
| Roth conversion added | $0 | $10,000 |
| 2026 standard deduction | −$15,750 | −$15,750 |
| Taxable income | $24,250 | $34,250 |
| Federal tax owed | $2,662 | $3,862 |
| Extra federal tax from the conversion | $1,200 (12.0% of $10,000) | |
Marginal vs effective: Your conversion spans the 12%–12% brackets. The headline 12.0% effective rate is lower than the 12% 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 $50,000. That stays under the 2026 first IRMAA tier ($109,000 for a single filer), 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 $50,000, you stay under the 400% FPL cliff ($60,240), so Marketplace subsidies are preserved. The ACA Subsidy Cliff Optimizer finds the largest conversion that keeps your credit.
Should you convert $10,000 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 12% 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 $10,000 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 (single filer)
- $25,000 conversion (single filer)
- $50,000 conversion (single filer)
- $75,000 conversion (single filer)
- $100,000 conversion (single filer)
- $150,000 conversion (single filer)
- $200,000 conversion (single filer)
Or switch filing status: $10,000 for married filing jointlys.
FAQ
How much tax will I pay on a $10,000 Roth conversion in 2026?
For a single filer with about $40,000 of other ordinary income, converting $10,000 adds roughly $1,200 in federal income tax — an effective rate of about 12.0% 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 12%. 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 $10,000 conversion trigger an IRMAA Medicare surcharge?
With this baseline, the conversion pushes MAGI to about $50,000, which stays under the 2026 first IRMAA tier ($109,000 for single filers), 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 $50,000 is below the 400% FPL cliff ($60,240), so Marketplace premium tax credits are preserved at this level.
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 $15,750 (single filer). Worked example assumes $40,000 of other ordinary income — your real numbers may differ; use the calculator above. Educational only, not tax advice.