Roth conversion plan for 2026 to 2035

How the plan is calculated

1. Baseline taxable income for the year: other income, taxable Social Security, and any RMD.⁴
2. Headroom to the top of your target bracket after the standard deduction and any age-65 additions.¹
3. Federal tax on the conversion, bracket by bracket, using the pro-rata rule for any after-tax basis.
4. State tax from your state's 2026 treatment of retirement income.
5. IRMAA two years later, from this year's MAGI against the 2026 tiers indexed at your inflation assumption.
6. RMD at your applicable age with and without the plan, from the IRS Uniform Lifetime Table.³
7. Lifetime tax and balances under both paths at your assumed return.

Years after 2026 use 2026 brackets and thresholds indexed at your inflation assumption. The IRS has not published them; the plan says so on every page.

2026 figures the plan uses

The two-year IRMAA look-back

Medicare sets your Part B and Part D premiums for a year using the income you reported two years earlier, so a conversion in 2026 shows up on your 2028 premium. The first surcharge tier in 2026 starts at $109,000 of MAGI for a single filer and adds about $96 a month, roughly $1,150 for the year, and the tiers above it climb fast.²

A plan that fills the 22% bracket can put you $13,000 over that line. The plan shows the surcharge in the year you pay it, not the year you cause it, and offers a second path that converts up to the tier line instead. Sometimes the extra $13,000 of conversion is worth $1,150 of premium and sometimes it is not, so both numbers sit side by side before you decide.

Roth conversion plan example: A single filer with $600,000 in an IRA

The filer is single, born in 1962, and living in New York, with $600,000 in a traditional IRA, no after-tax basis, and $30,000 of other income. They retire in 2027, start Social Security of $36,000 a year in 2032, fill the 22% bracket, and assume a 6% return and 2.5% inflation, with the tax paid from cash.

In 2026 the standard deduction of $16,100 leaves $13,900 of taxable income. The 22% bracket for a single filer ends at $105,700, so there is $91,800 of room. Converting all of it costs $4,380 at 12% on the first $36,500 and $12,166 at 22% on the remaining $55,300, for $16,546 of federal tax, an 18.0% effective rate on the conversion. MAGI lands at $121,800, which is $12,800 over the first IRMAA line, so 2028 Part B and D premiums rise by about $1,148. New York taxes the conversion after its $20,000 pension and annuity exclusion at 59½, about $3,943 of state tax.⁵

Years two to ten, the do-nothing comparison, and the IRMAA path are in the paid plan. The Roth conversion calculator runs a single conversion of any size with the same pro-rata rule, and the RMD calculator shows the first required distribution the plan is working to shrink.

Roth conversion rules

Roth conversions have no income limit and no annual cap, but a conversion cannot be undone: recharacterization ended with the 2017 tax law. Your RMD comes out first and cannot be converted, and the deadline is December 31, not tax day, so a conversion made in January 2027 is a 2027 conversion. Each conversion starts its own five-year clock for penalty-free access to the converted amount before 59½, separate from the five-year rule on Roth earnings.

If you have after-tax basis in any traditional IRA, the pro-rata rule taxes only the untaxed share of the conversion, across all your IRAs together, on Form 8606. The backdoor Roth guide walks through the pro-rata rule with numbers, and what a Roth IRA is covers the two five-year clocks.

When a conversion does not make sense

A Roth conversion does not make sense if you expect a lower tax rate later than now, or if you will need the converted money within five years and are under 59½. It also works against you if the only way to pay the tax is from the IRA itself before 59½, which adds a penalty, or if the balance is headed to charity, which pays no tax on it anyway. The last two cases, charity and a conversion that pushes a marketplace plan past the subsidy cliff before 65 when the lost credit is larger than the tax saved, are ones the plan checks for you in the explanation line.

The first case is the whole Roth versus traditional question, and the plan's break-even card puts a number on it for your inputs.

How Roth conversions change a surviving spouse's tax bill

For a married couple, when one spouse dies, the survivor files single on roughly the same income, in brackets about half as wide, with lower IRMAA lines, and takes RMDs alone. The plan shows the survivor's first full-year federal tax and Medicare surcharge with and without conversions, at an age you choose.