Social Security Tax Calculator: How Much of Your Benefit Is Taxable?
Run the combined-income worksheet
Use annual figures — your tax return is an annual document.
The thresholds
| Filing status | 50% tier starts above | 85% tier starts above | Set in |
|---|---|---|---|
| Single / head of household | $25,000 | $34,000 | 1983 / 1993 |
| Married filing jointly | $32,000 | $44,000 | 1983 / 1993 |
| Married filing separately (lived with spouse) | $0 | $0 | — (up to 85% from the first dollar) |
Between the two thresholds, the taxable amount is the lesser of half your benefits or half the excess over the first threshold — the "lesser-of" rule that keeps the tax phasing in gradually instead of cliff-jumping. Above the second threshold, the worksheet adds 85% of the further excess to the phased-in amount, capped at 85% of benefits. The full explanation, with worked examples, is on the are Social Security benefits taxable page; how each year's COLA pushes households up these frozen thresholds is covered on COLA and your taxes.
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Frequently asked questions
How is 'combined income' calculated?
Combined income (the IRS calls it provisional income) is your adjusted gross income excluding Social Security, plus any tax-exempt interest, plus one-half of your Social Security benefits. That single number is compared with the thresholds for your filing status.
What are the thresholds for taxing benefits?
For single filers and heads of household: $25,000 and $34,000. For married filing jointly: $32,000 and $44,000. Below the first threshold none of your benefits are taxable; between them, up to 50% can be taxable; above the second, up to 85%. The exact taxable amount follows the IRS worksheet — that is what the calculator above runs.
Have the thresholds ever been adjusted for inflation?
No. The $25,000/$32,000 pair dates from 1983 (effective 1984) and the $34,000/$44,000 pair from 1993. They are fixed in statute and are not indexed, which is why each year's COLA quietly pushes more beneficiaries over them.
Does this calculator tell me how much tax I will pay?
No — it estimates how much of your benefit is taxable income. The tax itself depends on your marginal bracket, the standard deduction (including the additional amount for taxpayers 65 and older), and any credits. Treat the result as the input to your tax return, not the bottom line.