How much of Social Security is taxable?
How much of a Social Security benefit is taxed depends on provisional income (also called combined income): half the benefit plus all other income, including tax-exempt interest. Below $25,000 ($32,000 for a couple filing jointly) none of the benefit is taxable. Above it, up to 50% is; above $34,000 ($44,000 joint), up to 85%. Those thresholds are written into the law and have never been raised for inflation. The calculator and tables are Coastline's engine, the same code that taxes the benefit in every year of a plan.
Taxable Social Security by other income
| Other income | Provisional income | Taxable benefits | Share taxable |
|---|---|---|---|
| $0 | $12,000 | $0 | 0% |
| $10,000 | $22,000 | $0 | 0% |
| $15,000 | $27,000 | $1,000 | 4% |
| $20,000 | $32,000 | $3,500 | 15% |
| $25,000 | $37,000 | $7,050 | 29% |
| $30,000 | $42,000 | $11,300 | 47% |
| $40,000 | $52,000 | $19,800 | 83% |
| $60,000 | $72,000 | $20,400 | 85% |
| Other income | Provisional income | Taxable benefits | Share taxable |
|---|---|---|---|
| $0 | $24,000 | $0 | 0% |
| $10,000 | $34,000 | $1,000 | 2% |
| $20,000 | $44,000 | $6,000 | 13% |
| $30,000 | $54,000 | $14,500 | 30% |
| $40,000 | $64,000 | $23,000 | 48% |
| $50,000 | $74,000 | $31,500 | 66% |
| $75,000 | $99,000 | $40,800 | 85% |
| $100,000 | $124,000 | $40,800 | 85% |
The taxable amount is never more than 85% of the benefit, however high the other income. Married people filing separately who lived with their spouse at any time in the year start at $0, so up to 85% of their benefit is taxable from the first dollar.
The tax torpedo
Inside the band where benefits are becoming taxable, each extra dollar of IRA withdrawal adds more than a dollar of taxable income: the dollar itself, plus 50 or 85 cents of benefits pulled into tax. That is the "tax torpedo". The table follows a single retiree, 67, with $30,000 of Social Security, as the IRA withdrawal grows (federal tax, 2026).
| IRA withdrawal | Taxable benefits | Federal tax | Tax on the next $1,000 | Benefits it makes taxable |
|---|---|---|---|---|
| $10,000 | $0 | $0 | $0 | $500 |
| $20,000 | $5,350 | $120 | $185 | $850 |
| $25,000 | $9,600 | $1,045 | $185 | $850 |
| $30,000 | $13,850 | $2,116 | $222 | $850 |
| $35,000 | $18,100 | $3,226 | $222 | $850 |
| $40,000 | $22,350 | $4,336 | $222 | $850 |
| $45,000 | $25,500 | $5,314 | $120 | $0 |
| $60,000 | $25,500 | $8,348 | $233 | $0 |
| $110,000 | $25,500 | $20,193 | $254 | $0 |
In the torpedo band the next $1,000 costs up to $222 (22.2%), on withdrawals from about $27,000 to $43,000, although this retiree is in the 12% bracket. Once 85% of the benefit is taxable the effect stops: at $44,000 the next $1,000 costs $120. Higher up, from $50,000 of withdrawals, the senior deduction's phase-out makes each extra dollar taxable as $1.06, because it takes 6 cents of the deduction away with it ($233 on the next $1,000 there). Roth conversions and capital gains count toward provisional income the same way as a withdrawal, which is why a conversion in the torpedo band costs more than the bracket alone suggests.
The rules
- Provisional income = one-half of benefits + all other income, including tax-exempt interest.
- First tier (up to 50% of benefits): over $25,000 for single, head of household and qualifying surviving spouse filers; over $32,000 on a joint return.
- Second tier (up to 85%): over $34,000, or $44,000 joint.
- Not indexed. The amounts are statutory (the first tier from 1983, the second from 1993) and the 2025 IRS worksheet still uses them, so a larger share of benefits becomes taxable over time.
- 2025 law. The One Big Beautiful Bill Act did not change these rules. Its $6,000 deduction for people 65 and older lowers taxable income instead: see the senior deduction calculator.
- States. A few states tax benefits too, each with its own rules: see states that tax Social Security in 2026.
Sources: IRS Publication 915, the IRS Social Security income FAQ, and 26 U.S.C. §86.
Educational, not tax advice. Federal tax only, 2026 brackets and deductions including the 65+ and senior deductions; the torpedo household's only income is Social Security and the IRA withdrawal.
Common questions
How much of my Social Security is taxable?
None if provisional income (half the benefit plus all other income, including tax-exempt interest) is $25,000 or less, or $32,000 on a joint return. Above that up to 50% is taxable, and above $34,000 ($44,000 joint) up to 85%. It is never more than 85% of the benefit.
Are the Social Security tax thresholds indexed for inflation?
No. They are fixed in the law, the first tier since 1983 and the second since 1993, and the IRS worksheet for 2025 still uses them.
What is the Social Security tax torpedo?
In the income band where benefits are becoming taxable, each extra dollar of other income also makes 50 or 85 cents of benefits taxable, so the tax on that dollar is well above the bracket rate. For a single retiree in the 12% bracket with $30,000 of benefits, the next $1,000 of IRA withdrawal costs up to $222 of federal tax (22.2%).
Did the 2025 tax law end the tax on Social Security?
No. It left the rules for taxing benefits unchanged and added a $6,000 deduction for each person 65 or older for 2025 through 2028, phased out at higher incomes.