How Bracket-Filling Roth Conversions Cut This Couple’s Tax Bill by $14,000 a Year

Picture a couple at 62 with $1.4 million in traditional IRAs, no pension, and a plan to delay Social Security until age 70 for the largest monthly check. Their personal balance sheet is healthy. Their worry is the tax bill in retirement, because almost every IRA dollar will come out as ordinary income.

This is where disciplined savers often land. One retiree on a finance forum captured the frustration simply: we did everything right with the 401(k) and now the IRS is our biggest beneficiary. Delaying Social Security to 70 boosts the eventual benefit by roughly 25% to 30%, real money for life, a point underscored in analysis of why supplemental tax-advantaged accounts matter alongside benefits. But waiting creates a window between retiring and claiming, and what happens in that window can rewrite the tax bill for the next two decades.

The Eight-Year Window That Changes Everything

What makes the stretch from 62 to 73 so valuable is how required minimum distributions (RMDs) interact with Social Security taxation. Once benefits start at 70 and required withdrawals kick in at 73, the two income streams stack. Above roughly $44,000 of combined income for a married couple, up to 85% of Social Security becomes taxable, and the marginal rate on the next IRA dollar jumps well above 12%.

Ages 62 through 69 are the only stretch when taxable income is essentially whatever the couple chooses. For 2026, a married couple filing jointly receives a $32,200 standard deduction, and the 12% bracket runs up to $100,800 of taxable income. By converting roughly $76,000 a year from the IRA to a Roth, they stay inside that 12% bracket. Over eight years, that is $608,000 moved out of the tax-deferred bucket at a blended federal cost of about $72,960.

Without conversions, that same $1.4 million balloons to roughly $2 million by age 70 and produces a first-year required distribution near $77,000. Stacked with $60,000 of combined Social Security, the couple lands around $159,000 of taxable income and a federal bill near $24,500 a year.

With conversions completed, the IRA is closer to $1.2 million by age 73. The required distribution falls to about $45,000, taxable income drops to roughly $115,000, and federal tax owed is closer to $12,500. That is an annual saving of $12,000 to $14,000, repeating for as long as both spouses live.

How the Pieces Fit Together

Conversions only work here because Social Security is delayed. If this couple claimed at 62, the 12% bracket would already be partly occupied by taxable benefits, leaving far less room to convert cheaply. Waiting until 70 keeps the bracket open for nearly a decade and locks in a larger lifetime benefit that, even after taxation, anchors the household budget.

One post-publication development strengthens the case for early conversions. The One Big Beautiful Bill Act, signed into law on July 4, 2025, created a new $6,000 per-person deduction for taxpayers 65 and older, available through tax year 2028. A married couple where both spouses qualify can claim $12,000 on top of the standard deduction. Because this couple starts converting at 62, they will hit 65 partway through the window, picking up three or four years of that additional deduction space. At a 12% marginal rate, a full $12,000 senior deduction saves approximately $1,440 in federal tax in each qualifying year. The deduction phases out for joint filers with modified adjusted gross income above $150,000, so keeping annual conversions sized to stay below that threshold preserves the full benefit.

Two practical details decide whether the broader strategy pays off. The conversion tax should be paid from a regular brokerage account rather than the IRA itself, so the full converted amount keeps compounding tax-free. The couple should also hold at least a year of living expenses in cash, because selling stocks in a falling market to fund a conversion can wipe out the tax savings in a single bad cycle.

What to Sit With Before Pulling the Trigger

Bracket-filling conversions are not free money. They pull a tax bill forward in exchange for a smaller one later, and the math depends on staying inside the 12% federal bracket each year. In a high-tax state, the combined cost can erase the advantage, so the strategy works best for couples with low state income tax or who plan to relocate. Across a 20-year retirement, federal tax savings of roughly $240,000 to $280,000 are realistic, with conversions paying for themselves in about six to seven years of retirement.

The costlier mistake is inaction. Reaching 73 and watching the first required distribution land on top of Social Security means the cheapest tax years have already passed. Every situation carries its own variables, and a conversation with a tax professional who can see the full picture is time well spent.

Editor’s note: This article corrects the 2026 12% bracket ceiling for married couples filing jointly from $96,950 to $100,800, per IRS Revenue Procedure 2025-32, and adjusts the annual conversion figure accordingly. It also adds context on the new OBBBA senior deduction of $6,000 per person (ages 65 and older, tax years 2025-2028) and notes how that provision interacts with a bracket-filling conversion strategy begun at age 62.

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