How Social Security is taxed (and why the thresholds catch almost everyone)
By the RetireGlide Team · June 24, 2026
Up to 85% of your Social Security benefit can be subject to federal income tax, determined by a formula called provisional income: your adjusted gross income, plus tax-exempt interest, plus half your Social Security. Because the thresholds — $25,000 single, $32,000 married — were set in 1983 and never indexed for inflation, most retirees with meaningful savings now pay tax on the majority of their benefit.
Note the phrasing: up to 85% of the benefit is taxable as income — not an 85% tax. A retiree in the 22% bracket with 85% of benefits taxable pays about 18.7 cents of tax per benefit dollar.
The provisional income formula
Compute provisional income: AGI (without Social Security) + tax-exempt interest + 50% of your annual benefit. Below the first threshold ($25k single / $32k joint), benefits are untaxed. Between the first and second thresholds ($34k / $44k), up to 50% becomes taxable. Above the second, up to 85% does. The percentages phase in, so each extra dollar of other income can drag $0.50–$0.85 of benefits into taxable income with it.
The tax torpedo
That drag creates what planners call the tax torpedo: in the phase-in range, withdrawing one more dollar from an IRA is taxed itself and makes up to 85 cents of Social Security newly taxable — an effective marginal rate that can spike to 1.85x your bracket (22% becomes ~40.7%) over a band of income. Retirees in the torpedo zone often benefit from unusual-looking strategies, like drawing pre-tax accounts before claiming benefits, precisely to avoid stacking the two later.
Since 2025, taxpayers 65 and older also get an additional senior deduction (up to $6,000 per person through 2028, phasing out at higher incomes), which shields more income for moderate-income retirees — but the provisional-income formula itself is unchanged, so the torpedo mechanics remain.
What you can actually control
The taxable share of your benefit is a function of your other income, which makes it plannable:
- Withdrawal sequencing — the mix of taxable, pre-tax, and Roth withdrawals in a given year moves provisional income directly; Roth withdrawals don't count toward it.
- Roth conversions before claiming — converting in the years between retirement and Social Security shrinks future RMDs and future provisional income.
- Claiming age — delaying benefits concentrates more income into fewer, larger checks, changing which thresholds you straddle.
- State taxes — most states don't tax Social Security, but a handful do; state choice interacts with everything above.
Frequently asked questions
- At what income is Social Security not taxed at all?
- If provisional income (AGI + tax-exempt interest + half your benefits) stays under $25,000 single or $32,000 married filing jointly, none of your benefit is federally taxable. Because the thresholds aren't inflation-indexed, fewer retirees clear them each year.
- Is it true 85% of my Social Security gets taken in tax?
- No — up to 85% of the benefit counts as taxable income, which is then taxed at your bracket. At the 22% bracket that's at most about 18.7% of the benefit paid in tax.
- Do Roth withdrawals make my Social Security taxable?
- No. Qualified Roth withdrawals are excluded from AGI and from provisional income — one of the reasons Roth dollars are disproportionately valuable after benefits begin.
- Did recent law changes eliminate taxes on Social Security?
- No. A temporary senior deduction (2025–2028) reduces taxable income for many retirees 65+, but benefits themselves are still taxed under the same provisional-income formula.
See this in your own plan
Run your numbers through the same engine — free, in about 3 minutes.
Keep learning
Sources
RetireGlide is an educational modeling tool, not an investment, tax, or legal adviser. Numbers that change annually (tax thresholds, premiums, benefit formulas) are approximate — always verify against the official sources above. Read our full disclaimer.