Is the phase-out 6 cents or 12 cents per dollar for a married couple?

Twelve, if both spouses are 65 or older. The IRS worksheet on Schedule 1-A reduces the $6,000 by 6% of the excess income, and each spouse enters that reduced amount. Two spouses, two reductions. A couple with $200,800 of adjusted gross income keeps $5,904 of the $12,000.

What does the senior deduction do to the cost of a conversion?

Inside the phase-out range, each converted dollar costs its bracket rate plus the tax on the deduction it erased. For the example couple at 76, a $100,000 conversion cuts the deduction from $12,000 to $5,904, and the conversion costs $18,687 of federal tax, a real rate of 18.7%.

Roth conversions · Deductions

How does the $6,000 senior deduction affect Roth conversions?

By Jim Swiech, CPA · Updated September 5, 2026

Quick answer

Two ways. It gives you more room: from 2025 through 2028, each spouse 65 or older gets an extra $6,000 deduction, $12,000 for a couple, so more of a conversion lands in the low brackets. And a conversion can take it away: the deduction shrinks by 6 cents for every dollar of modified adjusted gross income over $150,000 for a couple or $75,000single, applied to each person's $6,000 separately.

A single filer loses the whole deduction at $175,000. A couple both 65 or older loses both at $250,000. Inside that range a converted dollar costs its bracket rate plus the tax on the deduction it erased.

What the deduction is

The 2025 tax law added a temporary deduction of $6,000 for each taxpayer who is 65 or older by the end of the year, for tax years 2025 through 2028. It is on top of the regular standard deduction and the existing extra standard deduction for age, and you get it whether you itemize or not. A married couple must file jointly to claim it, and each person claiming it needs a Social Security number on the return. It is claimed on Schedule 1-A and flows to the front of Form 1040.

How the phase-out actually works

This is where most summaries go wrong. The IRS worksheet on Schedule 1-A takes the excess of modified adjusted gross income over the threshold, multiplies it by 6%, and subtracts that from $6,000. Then each spouse enters that reduced amount. So a couple both 65 or older loses 12 cents of total deduction for every dollar over $150,000, not 6, and the $12,000 is gone at $250,000. A single filer loses 6 cents per dollar over $75,000 and is at zero by $175,000. Modified adjusted gross income here is adjusted gross income for nearly everyone; unlike the Medicare calculation it does not add back tax-exempt interest.

2026, the deduction at various levels of modified adjusted gross income. Couple assumes both spouses are 65 or older.
Modified AGI	Single filer	Married couple, both 65+
$75,000 or less	$6,000	$12,000
$150,000	$1,500	$12,000
$200,800	$0	$5,904
$250,000 and up	$0	$0

What it does to a conversion

Take our example couple at 76: a $60,000 required minimum distribution and $48,000 of Social Security, adjusted gross income $100,000, comfortably under the line, full $12,000 deduction. Add a $100,000 conversion. Adjusted gross income becomes $200,800, the deduction falls to $5,904, and $6,096of deduction is gone. That lost deduction is taxed at the couple's bracket rate on top of the tax on the conversion itself, which is part of why a $100,000 conversion at this stage costs $18,687 in federal tax, a real rate of 18.7%, rather than the 22% bracket rate on the last dollars alone.

Inside the phase-out range, a couple in the 22% bracket pays 22 cents on each converted dollar plus 22% of the 12 cents of deduction it erased. The line at $150,000 of adjusted gross income is the ceiling on a conversion that applies only past 65, sitting below the first Medicare line and above the top of the 12% bracket for most retirees.

How to use it instead of losing it

If you are 65 or older and your income is under the threshold, the deduction is bracket room: a couple can have $12,000 more income at zero federal tax than before the 2025 law. That room is best filled by a conversion sized to stop under $150,000. If your income is already over the threshold, the deduction is partly gone anyway, and the question becomes whether a larger conversion that wipes it out entirely still beats the rate the IRA will face later. And because the deduction ends after 2028, the four years it exists add $12,000 of zero-rate room for a couple, which makes them cheaper than the same years without it; whether they beat your pre-Social-Security years depends on what else is on the return.

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Quick answers

How does the $6,000 senior deduction affect Roth conversions?: It adds room and it can be taken away. From 2025 through 2028 each spouse 65 or older gets an extra $6,000 deduction, $12,000 for a couple, so more of a conversion lands in the low brackets. But it shrinks 6 cents for every dollar of modified adjusted gross income over $150,000 for a couple or $75,000 single, applied to each person's $6,000 separately, so a couple both 65 or older loses all of it at $250,000 and a single filer at $175,000.
Is the phase-out 6 cents or 12 cents per dollar for a married couple?: Twelve, if both spouses are 65 or older. The IRS worksheet on Schedule 1-A reduces the $6,000 by 6% of the excess income, and each spouse enters that reduced amount. Two spouses, two reductions. A couple with $200,800 of adjusted gross income keeps $5,904 of the $12,000.
What does the senior deduction do to the cost of a conversion?: Inside the phase-out range, each converted dollar costs its bracket rate plus the tax on the deduction it erased. For the example couple at 76, a $100,000 conversion cuts the deduction from $12,000 to $5,904, and the conversion costs $18,687 of federal tax, a real rate of 18.7%.

Updated September 5, 2026. Reviewed by Jim Swiech, CPA.

Educational and general in nature. Not tax, legal or investment advice, and not a recommendation to convert. Figures are 2026 federal amounts under the assumptions stated on this page; your return has more lines than any example. Go Beyond Tax is a brand of Swiech Consulting LLC.