What is provisional income?

Provisional income, also called combined income, is adjusted gross income excluding Social Security, plus tax-exempt interest such as municipal bond income, plus 50% of Social Security benefits. It exists only to decide what share of benefits is taxable. Because tax-exempt interest counts, municipal bonds can raise the taxable share of a benefit even though the interest itself is never taxed.

Why are the Social Security tax thresholds never adjusted for inflation?

Because the statute does not index them. The $25,000 and $32,000 thresholds were set in 1983 and the $34,000 and $44,000 tiers in 1993, and neither has been raised since. Benefits rise with cost-of-living adjustments every year while the thresholds stay fixed, so the share of beneficiaries owing tax on benefits grows over time by design rather than by decision.

What is the Social Security tax torpedo?

The band of income where each extra dollar withdrawn also drags up to 85 cents of Social Security into taxable income, so taxable income rises by about $1.85 for every $1 withdrawn. The effective marginal rate is roughly double the statutory bracket while it lasts. It hits single filers hardest. For a single filer aged 65 with a $42,000 benefit in 2026, the effective federal rate reaches 43.1% between roughly $43,900 and $49,600 of IRA withdrawals, while the statutory bracket is 22%.

Does the tax torpedo affect married couples the same way?

Usually not. A married couple both aged 65 with $48,000 of combined benefits in 2026 has about $47,500 of deductions available, which absorbs most of the effect. Their torpedo tops out near 22.2%, not the 40%-plus figure often quoted. A couple generally needs combined benefits closer to $90,000 before the worst version appears.

Why does a surviving spouse often pay more tax on less income?

Three things change at once. The provisional income thresholds drop from $32,000 and $44,000 to $25,000 and $34,000, the tax brackets are roughly half as wide, and one standard deduction plus one age-65 deduction disappears. A survivor keeping the larger benefit and the same withdrawal can face a noticeably higher tax bill on lower total income than the couple did.

Learn · Social Security Taxes

Is Social Security Taxable? Yes, and There's a 43% Zone

Never more than 85% of the benefit gets taxed. But in one narrow band of withdrawals, an extra dollar costs 43 cents in federal tax while your bracket says 22%.

By Retire BFF Editorial Team Updated October 2026

The Short Answer

Whether your benefit gets taxed depends on provisional income: everything you earn apart from Social Security, plus any tax-exempt interest, plus half your benefit. Compare that one number to two thresholds.

Single filers owe nothing on benefits below $25,000 of provisional income. Between $25,000 and $34,000 up to half the benefit becomes taxable, and above $34,000 up to 85% does. Married filing jointly, the two thresholds are $32,000 and $44,000 instead. The 85% is a ceiling on how much of the benefit enters your taxable income. It is not a tax rate, and no one is ever taxed on the whole benefit.

Those four numbers were written into law in 1983 and 1993 and have never been adjusted for inflation. Benefits rise every year with the cost-of-living adjustment. The thresholds don't move. That gap is why a tax that originally reached about one retiree in ten now reaches most of them.

How the Two Tiers Actually Work

Most explanations stop at "up to 85% is taxable," which is where the confusion starts. People hear it as a rate. It isn't. It's the share of your benefit that gets added to the pile of income your ordinary tax brackets then apply to.

The formula works in layers. In the first tier you pick up 50 cents of taxable benefit per dollar of provisional income above the lower threshold. In the second tier the rate climbs to 85 cents per dollar, and it keeps going until 85% of the total benefit is counted. Then it stops permanently.

Provisional income	Single filer	Married filing jointly	What's taxable
Below the first threshold	Under $25,000	Under $32,000	None of the benefit
Between the thresholds	$25,000 to $34,000	$32,000 to $44,000	Up to 50% of the benefit
Above the second	Over $34,000	Over $44,000	Up to 85% of the benefit

Quick Fact Tax-exempt interest counts toward provisional income. Municipal bond income is never taxed directly, but it can still push more of your Social Security into the taxable column. It's one of the few places in the code where genuinely tax-free income raises your tax bill.

The Torpedo, and Who It Actually Hits

Here's where the mechanic turns strange. While you're inside the second tier, every extra dollar you withdraw does two things at once. It's taxable itself, and it drags another 85 cents of benefit into taxable income behind it. Your taxable income climbs by about $1.85 for each $1 you take out.

Run that against a 22% bracket and the real cost of that dollar isn't 22 cents. It's closer to 41. People call this the tax torpedo, and the figure usually quoted alongside it is 40.7%.

That number is real, but it travels with an assumption nobody states: you have to be in the 22% bracket while the phase-in is still running. Whether you are depends almost entirely on filing status. Take a single filer aged 65 with a $42,000 annual benefit in 2026, drawing increasing amounts from a traditional IRA.

IRA withdrawal	Taxable benefit	AGI	Federal tax	Rate on the next dollar
$20,000	$10,450	$30,450	$630	18.5%
$30,000	$18,950	$48,950	$2,728	22.2%
$40,000	$27,450	$67,450	$4,948	22.2%
$45,000	$31,700	$76,700	$6,295	43.1%
$50,000	$35,700	$85,700	$8,394	23.3%

The spike runs from roughly $43,900 to $49,600 of withdrawals and peaks at 43.1% in the middle of it. The statutory bracket through all of it is 22%. Each extra dollar adds $1.85 of taxable benefit and simultaneously shaves about 11 cents off the senior deduction, so taxable income rises by $1.96 per dollar withdrawn. Multiply by 22% and you get 43.1 cents.

Married couples mostly don't see this

Run the same arithmetic for a couple both aged 65 with $48,000 of combined benefits and the torpedo barely shows up. Their deductions in 2026 come to about $47,500, which is enough to keep them in the 12% bracket right through the phase-in. Their worst marginal rate is 22.2% rather than 43%. A couple generally needs combined benefits nearer $90,000 before the severe version appears.

So the honest version of the headline isn't "beware the torpedo." It's that the torpedo lands hardest on people filing alone, and a great deal of the alarmed writing about it describes a situation most married readers will never be in.

The Cheap Band Above the Spike

There's a second finding in the same arithmetic, and it points the opposite way from the scare framing.

Once 85% of your benefit is already counted, the drag stops. There's nothing left to pull in. Every dollar after that is taxed at your plain statutory rate, and for many households that rate is lower than the rate they just paid climbing through the phase-in.

For the married couple above, 85% of benefits is fully taxable once withdrawals pass about $61,100. From there to roughly $107,400 their marginal rate sits at a flat 12% the whole way. The expensive dollars were the ones in the phase-in. The dollars above it are among the cheapest they will ever withdraw.

That matters for anything involving deliberately realizing income, like a Roth conversion or deciding which account to tap first. Stopping a conversion partway up the phase-in can mean paying the highest rate in the whole range and then stopping right before the cheap part. Whether that's worth it turns on figures specific to the household, which is the kind of thing a tax preparer can run with your actual return in front of them.

What Happens When One Spouse Dies

This is the part almost nothing explains plainly, and it's the biggest single tax event in most retirements.

A surviving spouse keeps the larger of the two benefits. The smaller one stops. Household income falls. You might expect the tax bill to fall with it. It usually goes up, and often sharply, because three separate things change in the same year.

While both are alive

Combined benefits of $48,000, drawing $40,000 from the IRA
Thresholds of $32,000 and $44,000, wide brackets, two standard deductions and two age-65 deductions
AGI lands at $63,000

Federal tax: $1,550

The year after

Survivor keeps the larger $28,000 benefit and draws the same $40,000
Thresholds drop to $25,000 and $34,000, brackets roughly halve, one standard deduction and one senior deduction are gone
AGI lands at $61,500, which is lower than before

Federal tax: $4,234 on lower income.

Less money coming in, roughly two and a half times the federal tax. Nothing unusual happened. No one made a mistake. It's the ordinary consequence of moving from joint thresholds to single ones while the portfolio stays the same size.

It also reaches backward into a decision made years earlier. The higher earner's claiming age sets the survivor benefit, which is a large part of why the 62 versus 70 question looks different for a married couple than the single-person break-even math suggests.

Watch Out Every dollar figure here is 2026. The thresholds are permanent, but the deductions behind these results are not: the $6,000 per-person senior deduction is scheduled to expire after 2028, and the standard deduction moves every year. The shape of the effect lasts. The exact numbers won't.

Social Security Tax FAQ

Is Social Security taxable?

Sometimes, and never more than 85% of it. The test is provisional income: your income apart from Social Security, plus tax-exempt interest, plus half your benefit. Single filers below $25,000 owe nothing on benefits. Married filing jointly, the first threshold is $32,000. The 85% is a cap on how much of the benefit enters taxable income, not a rate applied to it.

What counts toward provisional income?

Adjusted gross income excluding Social Security, plus tax-exempt interest, plus 50% of your benefits. Municipal bond interest counts even though it is never taxed on its own, so tax-free income can still raise the taxable share of a benefit.

Why have the thresholds never changed?

The statute doesn't index them. The $25,000 and $32,000 figures date from 1983, the $34,000 and $44,000 tiers from 1993. Benefits rise with cost-of-living adjustments every year while the thresholds stay put, so a larger share of beneficiaries crosses them each year without anything being voted on.

What is the tax torpedo?

The band where each extra dollar withdrawn also pulls up to 85 cents of benefit into taxable income, so taxable income rises about $1.85 per dollar taken out. The effective rate runs near double the statutory bracket while it lasts. For a single filer aged 65 with a $42,000 benefit in 2026, it reaches 43.1% between roughly $43,900 and $49,600 of withdrawals, against a 22% statutory bracket.

Does it hit married couples the same way?

Usually not. A couple both 65 with $48,000 of combined benefits has around $47,500 of deductions in 2026, which keeps them in the 12% bracket through the phase-in and caps the effect near 22.2%. The severe version generally needs combined benefits closer to $90,000.

Can I avoid the tax on benefits entirely?

Only by keeping provisional income under the first threshold, which for most households means living on very little or on money that doesn't show up in AGI, such as Roth withdrawals or cash savings. For a household with a meaningful traditional IRA balance, required minimum distributions eventually make that difficult regardless of preference.

Retire BFF is an independent publisher, not a registered investment adviser, tax adviser, or financial planner. Everything here is general information about how the rules work, not advice about your situation. Figures are illustrative 2026 examples using published IRS amounts, and your own result depends on your full return. Confirm current figures at irs.gov and ssa.gov, and talk to a tax professional before acting.