Run a bracket ladder against 2026 federal brackets
Other taxable income is income after deductions that fills your brackets before the conversion: pension, interest, dividends, taxable Social Security, wages. Leave $0 for a pure gap year.
| Year | Conversion | Taxable Income | Tax on Conversion | Top Rate Reached | Cumulative Converted |
|---|
| Rate | Single: Taxable Income | Single: Tax at Top | Married Filing Jointly: Taxable Income | MFJ: Tax at Top |
|---|---|---|---|---|
| 10% | $0 – $12,400 | $1,240 | $0 – $24,800 | $2,480 |
| 12% | $12,400 – $50,400 | $5,800 | $24,800 – $100,800 | $11,600 |
| 22% | $50,400 – $105,700 | $17,966 | $100,800 – $211,400 | $35,932 |
| 24% | $105,700 – $201,775 | $41,024 | $211,400 – $403,550 | $82,048 |
| 32% | $201,775 – $256,225 | $58,448 | $403,550 – $512,450 | $116,896 |
| 35% | $256,225 – $640,600 | $192,979 | $512,450 – $768,700 | $206,584 |
| 37% | over $640,600 | — | over $768,700 | — |
These are the 2026 brackets from IRS Rev. Proc. 2025-32. "Tax at top" is the cumulative federal income tax owed at the top of that bracket, which is how the calculator builds each year's bill. Head-of-household thresholds sit between single and joint; this tool covers the two statuses most Roth planners use.
| Other Taxable Income | Single: Convert Up To | Married: Convert Up To |
|---|---|---|
| $0 | $50,400 | $100,800 |
| $20,000 | $30,400 | $80,800 |
| $40,000 | $10,400 | $60,800 |
| $60,000 | $0 (already past the top) | $40,800 |
Room equals the bracket cap minus your other taxable income. Dollars past the cap spill into 22%, which still beats the 24%+ rates many retirees pay once Required Minimum Distributions start at age 73.
A Roth conversion moves money from a traditional IRA or 401(k) into a Roth account. The converted amount counts as ordinary income in the year you convert, and in exchange every future dollar of growth and withdrawal is tax-free. Done carelessly, a conversion can land in the 22% or 24% bracket. Done as a ladder, it soaks up the 10% and 12% space you'd otherwise waste in a low-income year.
Tax is computed bracket by bracket: each slice of taxable income is taxed at its own rate, never the whole amount at your top rate. The calculator takes your other taxable income, adds each year's conversion slice, subtracts the tax you'd owe anyway, and reports the difference as the tax on that year's conversion. It also runs the entire conversion as a single year so you can see what laddering saves.
Enter your filing status and the taxable income you'll have anyway in a typical year, pensions and interest included. Pick the bracket you refuse to go over, 12% is the usual ceiling for a ladder. Then enter the total you're thinking of converting and how many years you'll spread it across. The ladder table shows each year's slice, the tax it triggers, and the top rate that year touches. Uneven splits front-load the remainder into the early years.
A married couple, both retired, has $20,000 of taxable income from interest and a small pension. They want $300,000 out of a traditional IRA. Converting all of it in one year stacks $320,000 of taxable income and triggers $59,996 of tax on the conversion, a 20.0% effective rate, with dollars reaching the 24% bracket.
Instead they convert $60,000 a year for 5 years. Each year, the first $4,800 of the conversion fills the rest of the 10% bracket ($480 of tax) and the remaining $55,200 lands in the 12% bracket ($6,624). That's $7,104 a year, $35,520 total, an effective rate of 11.84% on the full $300,000. Laddering under the 12% line saves $24,476, and every dollar now compounds tax-free in the Roth.
State income tax, the pro-rata rule if you have after-tax money in any traditional IRA, IRMAA Medicare surcharges set by income from two years prior, and the tax on Social Security benefits that extra income can trigger. Those can flip a marginal decision, so treat the result as a floor for a conversation with a tax professional, not a filing plan.
The 12% bracket tops out at $50,400 of taxable income for single filers and $100,800 for married filing jointly in 2026. Subtract your other taxable income from that cap and the difference is your conversion room. A married couple with $20,000 of other taxable income can convert $80,800 before any dollar hits the 22% bracket.
Conversions tend to pay off when your bracket today is lower than the bracket you expect in the future, which happens a lot between retirement and Required Minimum Distributions at age 73. Low-income years, a big future RMD pushing you into higher brackets, and leaving tax-free money to heirs are the three classic cases. If you expect to be in a lower bracket later, converting usually works against you.
No. Pre-tax dollars in a traditional IRA have never been taxed, so a conversion taxes them once as ordinary income. After that, qualified withdrawals are tax-free forever. The one trap is the pro-rata rule: if you have nondeductible (after-tax) contributions in any traditional IRA, each conversion is taxed proportionally on the pre-tax share, not on the dollars you pick.
Each conversion starts its own five-year clock for penalty-free access to converted principal if you're under 59½. Withdraw converted amounts before that clock runs and the 10% early-distribution penalty can apply. Earnings are separate: they need both age 59½ and a five-year period on the account to come out tax-free. Money converted after 59½ avoids the penalty clock entirely.
Medicare premiums. IRMAA surcharges are set by your modified adjusted gross income from two years earlier, and large conversions can push you over the 2026 thresholds, adding roughly $810 to $5,445 per person per year in Part B and D surcharges. Conversions can also raise taxes on Social Security benefits and reduce ACA premium subsidies if you're under 65.
The converted amount is ordinary income for the tax year of the conversion, so the tax is due with that year's return by the following April 15. You can pay from outside funds or have the custodian withhold, but paying the tax from the converted amount itself leaves you with less compounding in the Roth and, before 59½, can trigger the 10% penalty on the amount withheld.