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Married couples claiming Social Security in 2026 are running into a tax problem that rarely gets mentioned in retirement planning conversations, and it hits harder when two incomes combine than when one person claims alone.
A couple, both in their late 60s, each collecting Social Security. One spouse gets $1,800 a month, the other gets $1,400. Together that is $38,400 a year in benefits. They also have modest retirement account withdrawals of around $20,000 annually. On paper, this feels comfortable. The IRS treats them very differently than a single filer in the same situation.
Combined Social Security income: $38,400 annually
Additional retirement withdrawals: ~$20,000
Filing status: Married filing jointly
Core risk: Combined income triggers taxation of up to 85% of Social Security benefits
The IRS uses a concept called “combined income” to determine how much of your Social Security is taxable. The formula adds your adjusted gross income, any nontaxable interest, and half of your Social Security benefits. For married couples filing jointly, once combined income exceeds $44,000, up to 85% of Social Security benefits become taxable. That threshold has not been adjusted for inflation since it was set in 1983.
With the Consumer Price Index sitting at 326.6 against a 1982-84 baseline of 100, the purchasing power erosion is severe. Thresholds that once protected middle-income retirees now catch couples with relatively modest incomes. A single filer hits the 85% threshold at $34,000 in combined income. A married couple gets only $10,000 more runway despite having two people and typically higher fixed costs.
At $38,400 in combined benefits plus $20,000 in withdrawals, this couple lands well above the $44,000 threshold. Most of their Social Security check becomes federally taxable, turning what felt like a planning win into an unexpected tax bill.
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The single most effective lever is controlling the timing and source of retirement withdrawals. Pulling from a Roth IRA instead of a traditional IRA keeps combined income lower because Roth distributions are not counted in the IRS formula. Couples who convert traditional IRA balances to Roth accounts before both spouses claim Social Security can materially reduce how much of their benefits get taxed each year.
Claiming both Social Security benefits simultaneously without modeling the combined income tax impact first. Running the numbers before the lower-earning spouse files, and stress-testing different withdrawal sequences, is the decision that matters most. The gap between a planned approach and an unplanned one can easily reach several thousand dollars per year in avoidable federal taxes.