Consider Linda, a 64-year-old retiree with $1.1 million in a traditional 401(k). Her Social Security statement projects a monthly benefit of $5,181 if she waits until age 70. Instead of claiming early and leaving every dollar invested, she plans to use controlled 401(k) withdrawals to fund the next six years. The strategy initially sounds backward because retirement advice often emphasizes preserving savings for as long as possible. However, spending part of a tax-deferred account before Social Security and required minimum distributions begin can create valuable tax-planning opportunities. It may allow Linda to defer Social Security, reduce her future traditional retirement balance, and complete Roth conversions during relatively low-income years. That does not automatically make the strategy safe or optimal. Investment returns, taxes, Medicare premiums, longevity, and market conditions will determine whether the plan succeeds.
The 8% Increase Is Valuable, but It Is Not an Investment Return
Workers born in 1943 or later earn delayed retirement credits at an annual rate of 8% for waiting beyond full retirement age, with credits calculated monthly. The increase stops at age 70. Because Linda was born after 1960, her full retirement age is 67, meaning the 8% credits apply for three years, not for the entire period from 64 to 70. Waiting until 70 would make her benefit approximately 24% higher than it would be at 67, before accounting for applicable cost-of-living adjustments. Her advantage over claiming at 64 would be larger because claiming before full retirement age permanently reduces the starting benefit. The 2026 Social Security COLA was 2.8%, and COLAs generally apply even when an eligible worker has not started collecting. However, calling the delayed credit a “guaranteed 8% return” is misleading. Linda is purchasing a larger lifetime income stream, not earning an accessible return in an investment account. Its ultimate value depends heavily on how long she lives and whether survivor benefits are involved.
The $1.1 Million Bridge Requires More Than Simple Subtraction
Withdrawing $85,000 annually for six years would produce $510,000 of gross retirement-account distributions before taxes. That is less than half of Linda’s starting balance, but subtracting $510,000 from $1.1 million does not provide a reliable forecast. Her ending balance will depend on investment performance, the timing of gains and losses, inflation, taxes, fees, and whether $85,000 remains sufficient as living costs rise. Poor returns during the first several years of retirement can be especially damaging because withdrawals force the sale of assets while values are depressed. This is known as sequence-of-returns risk. The Bureau of Labor Statistics reported average annual expenditures of $78,535 per consumer unit in 2024, but that national figure includes households of different sizes, ages, incomes, and locations. It should not be treated as Linda’s required retirement budget. She needs a personalized spending plan that includes federal and state taxes, health insurance before Medicare, housing repairs, long-term care exposure, and an emergency reserve.
An $85,000 Withdrawal Will Not Stay Inside the 12% Bracket
The tax-planning opportunity is real, but the original bracket calculation needs adjustment. For 2026, a single filer has a standard deduction of $16,100, and the 12% federal bracket ends at $50,400 of taxable income. Assuming Linda has no other income, deductions, or unusual tax items, approximately $66,500 of gross ordinary income could be covered by the standard deduction and the 10% and 12% brackets. An $85,000 taxable 401(k) withdrawal would therefore push part of her income into the 22% marginal bracket. That does not mean every dollar would be taxed at 22%. Only the taxable income above the bracket boundary would face that rate. Interest, dividends, pensions, capital gains, and health-insurance subsidies could change the calculation substantially. After age 65, Linda may qualify for additional deductions, including the temporary enhanced senior deduction enacted for 2025 through 2028, but eligibility and phaseouts depend on income. Tax brackets should consequently be modeled one year at a time instead of using one withdrawal target for the entire six-year bridge.
Roth Conversions Could Reduce Linda’s Future RMDs
Linda’s years between retirement and required minimum distributions may provide an attractive Roth-conversion window. Because she was born after 1959, current federal law generally places her required minimum distribution starting age at 75. Each dollar converted from her traditional 401(k) or a rollover IRA into a Roth IRA becomes taxable income in the conversion year, but it also reduces the traditional balance used to calculate future RMDs. Qualified Roth IRA withdrawals are generally tax-free, and Roth IRA owners are not required to take lifetime RMDs. The problem is that Linda cannot assume she can withdraw $85,000 and then convert another $30,000 to $40,000 without consequences. That combination could push additional income through the 22% bracket, increase capital-gains taxes, reduce deductions, affect health-insurance subsidies, or trigger Medicare surcharges. The proper conversion amount is the difference between her projected taxable income and a carefully selected tax ceiling. That ceiling might be the top of a bracket, an IRMAA threshold, or another limit specific to her return.
Social Security Taxes and Medicare Premiums Can Change the Result
Delaying Social Security may allow Linda to recognize traditional retirement income before those benefits begin, but the tax rules require careful wording. Depending on combined income, up to 85% of Social Security benefits can be included in taxable income. That does not mean Social Security is taxed at an 85% rate. For a single filer, the current federal thresholds begin at $25,000, with the higher calculation applying above $34,000. Medicare creates another complication because income-related monthly adjustment amounts, or IRMAA, are generally based on tax information from two years earlier. For 2026 Medicare premiums, the first IRMAA tier begins when an individual’s modified adjusted gross income exceeds $109,000, not $106,000. Because Linda is approaching Medicare eligibility, withdrawals or conversions made at 63 or later could affect future Part B and Part D costs. A work stoppage or reduction may qualify as a life-changing event for requesting a new determination, but relief is not automatic and requires documentation.
The Break-Even Age Is Personal, Not Universal
Waiting until 70 often produces a claiming break-even point somewhere around a retiree’s early 80s, but there is no single age that applies to everyone. The answer changes with the starting claim age, benefit amount, taxes, investment returns, COLAs, marital status, and opportunity cost of spending portfolio assets. Someone in poor health or without other income may reasonably claim earlier. A higher-earning spouse may benefit more from delaying because the larger benefit can eventually support an eligible surviving spouse. Linda must also consider whether drawing down her portfolio leaves enough liquidity for medical expenses, home repairs, long-term care, and market downturns. The strongest version of this strategy is not simply “spend the 401(k) first.” It is a coordinated withdrawal plan that compares annual taxes, Medicare costs, portfolio sustainability, and lifetime Social Security income. Before acting, Linda should retrieve her personalized Social Security estimates, build a year-by-year tax projection, and test the plan under both strong and weak market-return assumptions.