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Social Security Tax Calculator: How Much of Your Benefits Are Taxable?
Quick answer
Data: Statutory thresholds (unchanged since 1993) · verified 2026-10-14 against IRS Publication 915. Runs entirely in your browser — nothing you type is sent or stored.
How the IRS formula works
The IRS does not tax Social Security on a simple income scale. It uses provisional income: your other income (AGI without benefits) + tax-exempt interest + half of your benefits. That number is compared to two fixed thresholds:
- Below the first threshold ($25,000 single / $32,000 joint): $0 of your benefits are taxable.
- Between the thresholds: the taxable amount is the smaller of 50% of your benefits or 50% of the amount over the first threshold.
- Above the second threshold ($34,000 single / $44,000 joint): 85% of the excess over the second threshold is added to the smaller of the tier-one amount or $4,500 (single) / $6,000 (joint) — but never more than 85% of your total benefits.
The calculator prints every line of this worksheet so you can follow it against IRS Publication 915 directly.
Worked example
A single retiree receives $24,000 in benefits and withdraws $30,000 from a traditional IRA. Provisional income: $30,000 + $12,000 (half of benefits) = $42,000. That is over the $34,000 second threshold, so: 85% × ($42,000 − $34,000) = $6,800, plus the capped tier-one amount of $4,500, gives $11,300. The 85% cap is 85% × $24,000 = $20,400, so the taxable amount is $11,300 — about 47% of the benefit. At a 12% marginal rate, the actual extra tax is roughly $1,356.
Common mistakes
- Confusing "85% taxable" with "85% tax." At most, 85% of the benefit is counted as income; tax is then owed at your normal bracket rate on that portion only.
- Leaving out tax-exempt interest. Municipal bond interest is tax-free itself, but it still counts in provisional income and can push more of your benefits into the taxable zone.
- Using monthly figures. This worksheet uses annual amounts — use Box 5 of your Form SSA-1099 for the year's total benefits.
- Ignoring the timing of IRA withdrawals. Because the thresholds are fixed, a large one-year withdrawal can make up to 85% of that year's benefits taxable. Spreading withdrawals can lower the total — our combined-income guide covers this in detail.
Frequently asked questions
At what income is Social Security not taxed at all?
If your provisional income — AGI without benefits, plus tax-exempt interest, plus half of your benefits — is at or below $25,000 (single) or $32,000 (married filing jointly), none of your benefits are taxable.
What is provisional income?
Your adjusted gross income not counting Social Security, plus any tax-exempt interest (like municipal bond interest), plus one half of your total Social Security benefits for the year. The IRS compares this number against the base amounts to decide how much of your benefits are taxable.
Is it true that 85% of my benefit can be taxed?
Up to 85% of the benefit can be included in taxable income — that is the cap. It does not mean an 85% tax rate. The included amount is then taxed at your ordinary rate, so the actual tax is far smaller.
Why haven't the $25,000 and $32,000 thresholds changed?
They were set by law in 1983 (and the second tier in 1993) and are not indexed for inflation. That is why more retirees owe tax on benefits every year.
Did the 2025 tax law make Social Security tax-free?
No. The One Big Beautiful Bill Act added an extra deduction of up to $6,000 per person for filers age 65+, which can offset the tax on benefits, but the taxation formula itself did not change. Use our Senior Deduction Calculator to see the new deduction.
What if I'm married filing separately?
If you lived with your spouse at any time during the year, your base amounts are $0, which usually makes 85% of your benefits taxable. If you lived apart all year, you use the single thresholds.
Do states tax Social Security too?
Most states do not. A handful tax benefits in some situations, usually with their own exemptions. This calculator covers federal tax only.
Official sources
- IRS Publication 915 — Social Security and Equivalent Railroad Retirement Benefits (last checked 2026-10-14)
- IRS — IRA FAQs on Social Security income (last checked 2026-10-14)
- SSA — Income taxes and your Social Security benefit (last checked 2026-10-14)
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Built and maintained by Thomas E. Wright, Senior Policy Editor, Housing & Tax. See our methodology and data changelog.
This tool provides estimates for general information only and is not legal, tax, or benefits advice. Final eligibility and amounts are determined solely by the administering agency. Privacy: all calculations run in your browser; we do not transmit, log, or store anything you enter.