She Retired at 64 With $380,000 in a 401(k) and No Income for Nine Years. She Never Converted a Dollar. Her First RMD Was Taxed at 22%.

A retiree who leaves work at 64 with a $380,000 401(k) balance and no earned income for the next nine years enters what planners call the gap years: the stretch between the last paycheck and the required beginning date when required minimum distributions (RMDs) kick in. An RMD is the amount the IRS forces out of a pre-tax retirement account each year once the required beginning date is reached. In the scenario laid out here, she did nothing during those years. She never converted a dollar to a Roth. When RMDs finally began, her first one was taxed at 22%. That outcome was avoidable, and every unused year carried a cost that compounded right alongside her balance.

Timeline: A Nine-Year Window That Was Legally Available

Under SECURE 2.0, the required beginning age depends on birth year. It is 73 for individuals born between 1951 and 1959, and 75 for those born in 1960 or later. A retiree who left work at 64 and took her first RMD nine years later reached her required beginning date at 73, which places her in the pre-1960 cohort. For someone born in 1960 or later, the same retirement age would open an eleven-year window rather than nine. However long the gap runs, it represents some of the most flexible tax years a retiree will ever occupy.

What Low-Income Gap Years Actually Look Like on a Tax Return

During those nine years between 64 and 73, she had no wages, no pension, and had not yet claimed Social Security. Her taxable income each year was close to zero. For 2026, the IRS set the single standard deduction at $16,100, and the 22% bracket begins above $50,400. A single filer with no other income can recognize a meaningful amount of taxable income each year and still stay within the lower brackets. Crucially, the One Big Beautiful Bill Act (OBBBA) added an additional $6,000 deduction for taxpayers age 65 and older, available through 2028 and phasing out above $75,000 in modified adjusted gross income. That extra shield means a qualifying gap-year retiree effectively has even more room to convert pre-tax dollars before hitting the 22% threshold, making the forgone years even costlier in retrospect.

Conversion Capacity Does Not Carry Forward

Every year she did not convert, that 12% bracket space expired forever. Meanwhile, her untouched $380,000 balance compounded. At an average 6% annual return over those nine years, the account swelled to roughly $642,000 by age 73. When her required beginning date arrived, the IRS Uniform Lifetime Table (divisor of 26.5 at age 73) mandated a first-year RMD of about $24,200. Stacked on top of the maximum Social Security benefit she began collecting at 70, where 85% is taxable, that mandatory distribution pushed her taxable income past the 12% ceiling of $50,400, ensuring the top dollars of her first RMD landed in the 22% bracket.

What a Conversion Plan Would Have Done

The standard playbook for someone in her position is annual partial Roth conversions sized to the top of a chosen bracket. A conversion moves money from a traditional 401(k) or IRA into a Roth, triggers ordinary income tax on the converted amount, and lets that money grow and be withdrawn tax-free afterward. Filling the 12% bracket each year for nine years would have shifted a large share of the pre-tax balance into a Roth at 12%, permanently shrinking the pool from which future RMDs are calculated. Those low-tax years between the last paycheck and the first RMD are the whole subject of our free Roth Window guide.

Two operational details matter here. First, pay the tax on each conversion from outside taxable savings rather than from the converted amount itself, so the full converted dollar keeps compounding inside the Roth. Second, coordinate conversions with the Social Security claiming decision, because once benefits begin, more of every conversion dollar gets taxed, and more of Social Security itself becomes taxable.

Broader Context

The 10-year Treasury yield climbed to approximately 5.00% in mid-September 2026, up sharply from 4.67% in late August, following a Federal Reserve rate increase. The 2027 Social Security COLA is now tracking in a range of 3.5% to 3.6%, above earlier projections of around 3.1%, with AARP forecasting 3.6% and the Senior Citizens League at 3.5%. Both developments underscore the same pressure: a retiree relying on Social Security plus mandatory withdrawals will see the taxable share of income rise mechanically as balances compound and benefits adjust upward.

What the Case Actually Shows

The nine-year window was the cheapest tax environment she would ever occupy. Leaving it untouched concentrated the tax bill into the years when she had the least flexibility, on a balance that had grown at a rate set by the interaction of RMDs and Social Security rather than by anything she chose. The gap years do not wait, and their capacity to shelter conversions does not roll over.

Editor’s note: This article has been updated to reflect the 10-year Treasury yield rising to approximately 5.00% in mid-September 2026 (from 4.67% in late August), the 2027 Social Security COLA forecast moving up to a range of 3.5% to 3.6% from the earlier 3.1% estimate, and the OBBBA’s additional $6,000 deduction for taxpayers age 65 and older, which expands gap-year conversion capacity for qualifying retirees.

Contact [email protected] for any questions or corrections.