Deorbit Plan

Roth conversion room left in 2026

How much more you can convert before the next bracket, IRMAA tier, ACA cliff or deduction phase-out

By the Deorbit Plan editorial team, a Berrydyne program · Last reviewed · Topic: Roth conversions

What it computes

Near the end of the year you know roughly what you have earned and withdrawn. This tool takes that income and lists, nearest first, how much more you could convert to a Roth before reaching each line that changes the price of the next dollar: the top of each federal bracket[8], each Medicare IRMAA tier (set by this year’s income, charged two years later)[6], the ACA cliff if you buy marketplace coverage[1], and the income at which the temporary senior deduction starts to shrink[10]. Each line is found to the dollar with the simulator’s own tax functions, including the extra Social Security that a conversion makes taxable.

Roth conversion room left this year

The first line you would reach is the top of the 12% bracket: you can convert $63,150 more this year before crossing it, for about $8,178 in federal income tax (13% of the conversion).

How much more you can convert before each line, nearest first. Today: taxable ordinary income $37,650, MAGI for Medicare IRMAA $81,500, MAGI for the ACA $86,000 (it also counts untaxed Social Security).

LineThresholdRoomTax on it
Top of the 10% bracket$24,800taxable incomeAlready pastn/a
Top of the 12% bracket$100,800taxable income$63,150$8,17813% of it
Senior deduction starts to shrink$150,000AGI$68,500$9,35513.7% of it
IRMAA tier 1 (2028 premiums)$218,000IRMAA MAGI$136,500$25,21318.5% of it
Top of the 22% bracket$211,400taxable income$167,792$32,51019.4% of it
IRMAA tier 2 (2028 premiums)$274,000IRMAA MAGI$192,500$38,60220.1% of it
IRMAA tier 3 (2028 premiums)$342,000IRMAA MAGI$260,500$54,92221.1% of it
IRMAA tier 4 (2028 premiums)$410,000IRMAA MAGI$328,500$71,24221.7% of it
Top of the 24% bracket$403,550taxable income$359,900$78,77821.9% of it
Top of the 32% bracket$512,450taxable income$468,800$113,62624.2% of it
IRMAA tier 5 (2028 premiums)$750,000IRMAA MAGI$668,500$183,72127.5% of it
Top of the 35% bracket$768,700taxable income$725,050$203,51428.1% of it

Federal income tax only, including the extra Social Security that becomes taxable. IRMAA rows use this year’s tiers; the tiers that apply 2 years from now will be indexed and are not yet published.

Worked example

A married couple aged 66 and 64 has $52,000 of pension and IRA income so far, $30,000 of Social Security and $4,000 of dividends. The nearest lines are:

  • Top of the 12% bracket: $63,150 of room, costing $8,178 in federal tax (13%).
  • Senior deduction starts to shrink: $68,500 of room, costing $9,355 in federal tax (13.7%).
  • IRMAA tier 1 (2028 premiums): $136,500 of room, costing $25,213 in federal tax (18.5%).

The effective rates are higher than the bracket rates because the conversion also pushes this couple’s dividends out of the 0% capital-gains band. Their Social Security is already 85% taxable, so the conversion makes no more of it taxable here; at lower incomes it can. Filling a bracket to its top is the usual target, stopping a margin short of any IRMAA or ACA line.

What it ignores

  • State income tax.
  • Withholding and estimated-tax deadlines: a conversion late in the year can create an underpayment unless enough tax is paid in time.
  • Inflation indexing of IRMAA tiers by the time they apply, and the IRMAA and ACA dollar costs themselves. The IRMAA calculator and ACA cliff calculator price them.
  • Itemized deductions, credits, and the pro-rata rule if you have after-tax IRA basis.
  • Whether converting is worth it at all, which depends on your tax rates in later years.

The rule behind it

The full explanation, with sources, is in One MAGI budget: why Roth conversions and ACA subsidies fight.

See it over a full plan

The room changes every year as income, Social Security and RMDs change. The simulator can size each year’s conversion to fill a bracket while staying a safety margin below the IRMAA and ACA lines. Open it in the simulator →

If you already have a saved plan, the link only takes you to the right panel; your plan is not changed.

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This tool shows how the rules work. It is not financial, tax or investment advice. See the disclaimer.

Sources