Social Security · 9 min read
The Social Security Tax Torpedo: How $1 of IRA Income Can Create $1.85 of Taxable Income in 2026
The tax torpedo is the income zone where each extra dollar also makes Social Security taxable. Above $44,000 of provisional income for a married couple ($34,000 single), a threshold never indexed for inflation, one more IRA dollar adds up to $0.85 of taxable benefits: $1 + $0.85 = $1.85 taxed. In the 12 percent bracket, that is 22.2 percent.
Retirees who draw from a traditional IRA while collecting Social Security sometimes find that a modest withdrawal raised their federal tax by far more than their bracket implied. Nothing went wrong on the return. The withdrawal did two things at once: it added income, and it made part of the Social Security benefit taxable that had not been before. Planners call the result the Social Security tax torpedo. It is predictable once the formula is laid out, and it applies only within a band of income that can be located in advance.
What follows is educational and covers federal income tax. How it applies to a particular return should be confirmed with a tax professional.
What the Torpedo Question Is Really Asking
Behind “why did my tax jump?” is a question about marginal rates. The bracket table shows the rate charged on the next dollar of taxable income. For a retiree whose benefits are partly taxable, the next dollar of IRA income can create more than one dollar of taxable income, so the rate that matters is the bracket multiplied by that ratio. Three numbers decide it: provisional income, the two thresholds, and how much of the benefit is already taxable.
The Rules: Provisional Income and Two Thresholds
Section 86 of the tax code measures a household’s income for this purpose with its own yardstick, usually called provisional income. (26 U.S.C. §86; IRS Publication 915)
Provisional income = adjusted gross income + tax-exempt interest + ½ of the year’s Social Security benefits
That figure is compared with two thresholds that set how much of each added dollar of income pulls benefits into taxable income.
| Provisional income | Single | Married filing jointly | Benefit dollars made taxable per added dollar |
|---|---|---|---|
| Below the first threshold | Up to $25,000 | Up to $32,000 | None |
| Between the thresholds | $25,000 to $34,000 | $32,000 to $44,000 | $0.50, up to 50% of benefits |
| Above the second threshold | Over $34,000 | Over $44,000 | $0.85, until 85% of benefits is taxable |
The two tiers were written at different times. The first tier, $25,000 single and $32,000 joint, comes from the Social Security Amendments of 1983 and applied from 1984; the second tier, $34,000 and $44,000, was added by the Omnibus Budget Reconciliation Act of 1993 and took effect in 1994. Neither tier is indexed for inflation. (SSA Issue Paper 2015-02; 26 U.S.C. §86) Benefits and other retirement income rise with prices and wages while the lines stay put, so each year more households cross them.
Two details of the formula matter later. Tax-exempt municipal bond interest is added back, so it counts here even though it is not taxed itself. And the ceiling is firm: no more than 85 percent of the benefit is ever taxable.
The Arithmetic: How $1 Becomes $1.85
Above the second threshold, and until the 85 percent ceiling is reached, one more dollar from a traditional IRA does two things:
- It is ordinary income itself: $1.00 of taxable income.
- It raises provisional income by $1.00, which makes 85% × $1.00 = $0.85 of previously untaxed benefits taxable.
Together, $1.00 + $0.85 = $1.85 of taxable income per dollar withdrawn. The bracket rate applies to the whole $1.85.
| Where the dollar lands | Taxable income created | Effective marginal rate |
|---|---|---|
| 10% bracket, 85% zone | $1.85 | 10% × 1.85 = 18.5% |
| 12% bracket, 50% zone | $1.50 | 12% × 1.50 = 18.0% |
| 12% bracket, 85% zone | $1.85 | 12% × 1.85 = 22.2% |
| 22% bracket, 85% zone | $1.85 | 22% × 1.85 = 40.7% |
| Any bracket, 85% ceiling already reached | $1.00 | The bracket rate |
The $1.85 is taxable income, not tax. What it changes is the rate: a dollar the bracket table prices at 12 percent actually costs 22.2 cents. For married couples, the 22 percent row is less common in 2026 because the larger standard deduction pushes the top of the 12 percent bracket higher; single filers with moderate benefits reach it more often.
In the 85 percent zone, the true marginal rate is the bracket times 1.85. The zone has a beginning and an end, and both can be calculated for a specific household.
A Hypothetical Couple, Worked Through
This illustration is hypothetical and simplified. It is not based on any client, uses 2026 federal figures only, ignores state tax, and is not a recommendation.
A married couple, both 67, file jointly in 2026. Their combined Social Security benefit is $50,000 and their only other income is withdrawals from traditional IRAs. Because both are over 65 and their income is well under the $150,000 phase-out, their deductions total $47,500: the $32,200 standard deduction, $3,300 of age-based additions, and $12,000 of senior deduction. (IRS Rev. Proc. 2025-32; 26 U.S.C. §151(d)(5)) The 10 percent bracket covers the first $24,800 of taxable income and the 12 percent bracket runs to $100,800.
| IRA withdrawals | $30,000 | $50,000 | $70,000 |
|---|---|---|---|
| Provisional income (IRA + ½ of $50,000) | $55,000 | $75,000 | $95,000 |
| Taxable Social Security | $15,350 | $32,350 | $42,500 (the 85% ceiling) |
| Adjusted gross income | $45,350 | $82,350 | $112,500 |
| Taxable income (AGI − $47,500) | $0 | $34,850 | $65,000 |
| Federal income tax | $0 | $3,686 | $7,304 |
| Added tax on the next $1,000 withdrawn | $0 | $222 | $120 |
At $50,000 of withdrawals, taxable Social Security is 85% × ($75,000 − $44,000) + $6,000 = $26,350 + $6,000 = $32,350. The $6,000 is the most the 50 percent tier can contribute for a couple, half of the $12,000 gap between the two thresholds. One more $1,000 raises taxable benefits by $850, so taxable income rises by $1,850 and tax by 12% × $1,850 = $222. At $70,000, 85 percent of the benefit ($42,500) is already taxable, so the next $1,000 adds only $1,000 of taxable income and $120 of tax. The same withdrawal costs 85 percent more in the middle of the range than at the top of it.
For this couple the zones fall at these withdrawal levels:
- Up to about $31,200: no federal income tax, because taxable income stays under the $47,500 of deductions, even though some benefits are already taxable.
- About $31,200 to $44,600: the 10 percent bracket in the 85 percent zone, an effective 18.5 percent.
- About $44,600 to $61,900: the 12 percent bracket in the 85 percent zone, an effective 22.2 percent. This is the torpedo in its usual form.
- Above about $61,900: 85 percent of the benefit is taxable and the marginal rate returns to 12 percent.
The upper edge comes from solving for the point where 85% × (provisional income − $44,000) + $6,000 reaches the $42,500 ceiling: provisional income of about $86,900, or about $61,900 of withdrawals. A larger benefit moves every boundary; the method stays the same.
For this couple, $1,000 more from the IRA costs $222 at $50,000 of withdrawals and $120 at $70,000. The difference is entirely the Social Security benefit being pulled into taxable income.
How We Approach This in a Plan
We treat the torpedo as a map of a household’s marginal rates rather than a problem to be avoided at any cost. The zone is where the price of income is highest, so the planning work is deciding which income lands there and which lands elsewhere.
- Taxes and account order. Spending from a Roth IRA or from taxable savings instead of a traditional IRA can keep provisional income below the zone in some years. Qualified Roth withdrawals are not part of adjusted gross income, so they add nothing to provisional income. Our guide to withdrawal sequencing covers how the order of accounts changes the tax bill.
- Social Security timing. Income recognized before benefits start faces only the bracket, because there is no benefit yet to be pulled in. The years between retirement and claiming are often when Roth conversions are cheapest, and delaying the claim widens that window. The claiming decision itself is covered in our Social Security claiming framework.
- Required distributions. RMDs are ordinary income that grows with the account, and they can push a household into the zone without any discretionary decision. From age 70½, qualified charitable distributions of up to $111,000 per person in 2026 can satisfy an RMD while staying out of adjusted gross income. (IRS Notice 2025-67)
- Medicare. The same income that sets taxable benefits also sets Medicare premiums two years later. (20 CFR §418.1135) A household that climbs past the torpedo zone with a large conversion should check the distance to the IRMAA cliff, which works by thresholds rather than a slope.
- Deductions. The temporary senior deduction lowers taxable income but does not change how benefits are taxed; see the $6,000 senior deduction. Its phase-out above $150,000 of joint modified AGI is a separate rate effect for higher-income couples.
The output is a year-by-year schedule showing where each household’s zones begin and end, which accounts fund spending, and where conversions or gains fit. We revisit it when benefits, balances or tax law change.
Questions Worth Answering Before You Decide
- What is the household’s provisional income this year, including tax-exempt interest, and how far is it from $32,000 and $44,000 (or $25,000 and $34,000 if single)?
- How much of the benefit is already taxable, and how many more dollars of income until the 85 percent ceiling is reached?
- Which bracket does the next dollar land in after the standard, age-based and senior deductions?
- Are there Roth or taxable-account dollars that could fund spending in years when IRA income would fall inside the zone?
- Would a conversion or capital gain this year push the household through the zone, and what does that do to Medicare premiums two years out?
- When do required distributions begin, and how large are they projected to be?
What This Does Not Mean
- It does not mean $1 of withdrawal costs $1.85 in tax. It creates up to $1.85 of taxable income, which is then taxed at the bracket rate.
- It does not mean IRA withdrawals should be avoided. Pre-tax money is taxed eventually; the question is at what marginal rate, and sometimes the zone is the cheapest place it will ever be taxed.
- It does not mean all of the benefit is taxable. The federal ceiling is 85 percent, and below the first threshold none of it is.
- It does not describe state tax. State treatment of Social Security varies and is outside this guide.
- It is not personalized advice. How the thresholds apply to a particular return belongs with a tax professional who can see all of the household’s income.
Frequently Asked Questions
Q: What is provisional income?
Adjusted gross income, plus tax-exempt interest, plus half of the year’s Social Security benefits. The IRS compares it with $25,000 and $34,000 for single filers, or $32,000 and $44,000 for married couples filing jointly, to decide how much of the benefit is taxable.
Q: Why is it called the Social Security tax torpedo?
Because the extra tax arrives below the waterline of the bracket table. In the 85 percent zone, each added dollar of IRA income makes up to $1.85 taxable, so a 12 percent bracket behaves like 22.2 percent and a 22 percent bracket like roughly 40.7 percent.
Q: Have the $32,000 and $44,000 thresholds been the same since 1984?
Only the first tier has. The $25,000 and $32,000 thresholds date from the 1983 Social Security Amendments, effective in 1984. The $34,000 and $44,000 thresholds were added in 1993 and took effect in 1994. Neither tier is indexed for inflation.
Q: What is the most Social Security that can be taxed?
Eighty-five percent of the benefit, however high income goes. Once 85 percent is already included, additional income no longer pulls in benefits and the torpedo ends. Below $32,000 of provisional income for a couple, or $25,000 for a single filer, no benefit is taxable.
Q: Does the 2025 senior deduction stop Social Security from being taxed?
No. The $6,000 deduction for people 65 and older, available for 2025 through 2028, reduces taxable income after the fact. The provisional-income formula that decides how much of the benefit counts as income is unchanged.
Q: Which income stays out of the calculation?
Qualified Roth IRA withdrawals and qualified charitable distributions, up to $111,000 per person in 2026 for IRA owners 70½ or older, stay out of adjusted gross income and so out of provisional income. Traditional IRA and 401(k) withdrawals, pensions, capital gains, interest and tax-exempt municipal interest all count.
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General educational information, current as of 2026. Figures and rules change. For guidance specific to your situation, speak with a qualified professional.