Social Security Tax Calculator
How much of your benefits is taxable, by IRS Worksheet 1
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Age only changes the tax estimate, through the 2026 extra standard deduction and senior deduction. A qualifying surviving spouse gets the single base amounts on the worksheet and the joint brackets and standard deduction in the tax estimate.
Taxable part of your Social Security
$28,100
Share taxable
70.3%
Combined income
$70,000
Federal tax it adds
$2,926
Your combined income of $70,000 is above $44,000, so up to 85% of your benefits can be taxable. Another $1,000 of other income would make $850 more of your benefits taxable and add about $222 of federal tax.
2026 federal income tax estimate
Standard deduction, with the extra amounts for age 65 and over
| Adjusted gross income | $78,100 |
| Deductions | $47,500 |
| Taxable income | $30,600 |
| Federal income tax | $3,176 |
| Top bracket | 12% |
| Tax added by your benefits | $2,926 |
Federal only, before credits, the alternative minimum tax and the 3.8% net investment income tax. All other income is taxed at ordinary rates here, so the estimate is too high if part of it is qualified dividends or long-term gains; use the capital gains tax calculator for those.
Your Worksheet 1, line by line
Line numbers from IRS Publication 915
| Line | What it is | Amount |
|---|---|---|
| 1 | Social Security benefits (box 5) | $40,000 |
| 2 | Half of line 1 | $20,000 |
| 3 | Other taxable income | $50,000 |
| 4 | Tax-exempt interest | $0 |
| 6 | Lines 2 + 3 + 4 (line 5 taken as zero) | $70,000 |
| 7 | Adjustments to income | $0 |
| 8 | Combined income: line 6 minus line 7 | $70,000 |
| 9 | Base amount | $32,000 |
| 10 | Line 8 minus line 9 | $38,000 |
| 11 | Width of the 50% band | $12,000 |
| 12 | Line 10 minus line 11, not below zero | $26,000 |
| 13 | Smaller of line 10 or line 11 | $12,000 |
| 14 | Half of line 13 | $6,000 |
| 15 | Smaller of line 2 or line 14 | $6,000 |
| 16 | 85% of line 12 | $22,100 |
| 17 | Line 15 + line 16 | $28,100 |
| 18 | 85% of line 1, the most that can be taxable | $34,000 |
| 19 | Taxable benefits: smaller of line 17 or line 18 | $28,100 |
If line 8 is not more than line 9, none of your benefits are taxable. Line 5 (exclusions for adoption benefits, foreign earned income and some American Samoa or Puerto Rico income) is taken as zero.
By the Coast FIRE Calculator editorial team · Methodology · Official sources: IRS Publication 915: Social Security and equivalent railroad retirement benefits (Worksheet 1); 26 U.S.C. 86: Social Security and tier 1 railroad retirement benefits (base amounts) · Sources checked September 27, 2026 · Corrections: hello@coastfirecalculator.io
How much of your Social Security is taxable
The IRS compares your combined income with a base amount for your filing status. Combined income is half of your benefits plus all your other income, including tax-exempt interest, minus certain adjustments to income (line 8 of the IRS worksheet; the Social Security Administration calls it combined income). At or below the base amount, none of your benefits are taxable. Above it, up to 50% can be; above the adjusted base amount, up to 85%.
These amounts are written into the tax code (section 86) and are not adjusted for inflation, so they apply unchanged in 2026. On a joint return you add both spouses' income and benefits, even if only one of you receives Social Security.
| Filing status | Base amount (50% tier) | Adjusted base amount (85% tier) |
|---|---|---|
| Single, head of household or qualifying surviving spouse | $25,000 | $34,000 |
| Married filing jointly | $32,000 | $44,000 |
| Married filing separately, lived apart from your spouse all year | $25,000 | $34,000 |
| Married filing separately, lived with your spouse at any time in the year | $0 | $0 |
From IRC section 86(c) and IRS Publication 915 (2025), checked September 27, 2026. The 2025 edition was the newest on irs.gov that day. A qualifying surviving spouse uses the single amounts here but the joint brackets and standard deduction for the tax itself.
How the IRS worksheet works
- Combined income. Add half of your benefits (box 5 of Form SSA-1099), your other taxable income (wages, taxable interest, dividends, taxable IRA and pension income, capital gains and Schedule 1 income) and tax-exempt interest. Subtract adjustments to income from Schedule 1 lines 11 to 20, 23 and 25; student loan interest is not subtracted.
- The 50% band. Take half of what is over the base amount, up to the adjusted base amount. That is at most $4,500 ($6,000 on a joint return), and never more than half of your benefits.
- The 85% band. Add 85% of what is over the adjusted base amount.
- The cap. The taxable part is the smaller of that total and 85% of your benefits.
| Combined income | Taxable part of your benefits |
|---|---|
| Up to the base amount | None |
| Above the base, up to the adjusted base | Half of the amount over the base, but no more than half of your benefits |
| Above the adjusted base | 85% of the amount over the adjusted base, plus the smaller of half your benefits or $4,500 ($6,000 joint), but no more than 85% of your benefits |
Married filing separately and living with your spouse at any time in the year, you skip the bands: the taxable part is the smaller of 85% of combined income and 85% of your benefits.
The IRS examples, run through this calculator
| Publication 915 | Filing status | Benefits | Other income | Combined income | IRS result | Calculator |
|---|---|---|---|---|---|---|
| Worksheet A example | Single | $1,500 | $17,700 | $18,450 | $0 | $0 |
| Example 1 | Single | $5,980 | $28,990 | $31,980 | $2,990 | $2,990 |
| Example 2 ($1,000 IRA deduction) | Married filing jointly | $5,600 | $29,750 | $31,550 | $0 | $0 |
| Example 3 | Married filing jointly | $10,000 | $40,500 | $45,500 | $6,275 | $6,275 |
| Example 4 | Separately, lived together | $4,000 | $8,000 | $10,000 | $3,400 | $3,400 |
The worked examples in IRS Publication 915 (2025). In Example 3 the $10,000 is the Social Security equivalent part of tier 1 railroad retirement benefits, which is taxed the same way. Their $40,500 includes $200 of savings bond interest excluded on Form 8815, which Worksheet 1 adds back by using Schedule B line 2 instead of Form 1040 line 2b.
Federal tax on your benefits in 2026
The taxable part of your benefits is added to your other income and taxed at your normal rates. The calculator works out your 2026 federal income tax with the standard deduction ($16,100 single, $32,200 married filing jointly or qualifying surviving spouse, $24,150 head of household), the extra standard deduction for age 65 and over ($2,050 if unmarried and not a surviving spouse, $1,650 each if married or a qualifying surviving spouse), and the senior deduction of $6,000 per person 65 or older for 2025 to 2028. The senior deduction shrinks by 6% of modified AGI above $75,000 ($150,000 on a joint return; a qualifying surviving spouse does not file jointly, so $75,000 applies) and is not available when married people file separately. A qualifying surviving spouse is taxed with the joint brackets. It then shows how much of the tax comes from your benefits: the tax with them minus the tax without them.
The senior deduction and the standard deduction are taken after adjusted gross income, so they do not change the taxable part of your benefits, only the tax on it. Money that raises your other income, such as a Roth conversion, a traditional IRA withdrawal or a required minimum distribution, can make more of your benefits taxable as well as being taxed itself. Qualified Roth IRA distributions are not included in income and do not count.
The estimate taxes all other income at ordinary rates; qualified dividends and long-term gains usually owe less (see the capital gains tax calculator). It also leaves out itemized deductions, credits, the alternative minimum tax, the 3.8% net investment income tax and state tax.
When to use the IRS worksheets instead
- You contributed to a traditional IRA and you or your spouse is covered by a retirement plan at work: the IRA deduction and the taxable benefits are worked out together with the worksheets in Publication 590-A.
- You exclude interest from Series EE or I savings bonds (Form 8815), adoption benefits, foreign earned income or housing, or income from American Samoa or Puerto Rico: use Worksheet 1 in Publication 915.
- You received a lump-sum payment of benefits for an earlier year: the lump-sum election in Publication 915 may lower the taxable amount.
- You are a nonresident alien: the worksheet does not apply. Instead 85% of your benefits is taxed at 30%, unless a tax treaty exempts them or sets a lower rate; residents of Switzerland are taxed at 15% of the total benefit. Publication 915 lists the treaty countries and points to Publication 519 for who is a nonresident alien.
- You are a U.S. citizen living in Canada, Egypt, Germany, Ireland, Israel, Italy (if also an Italian citizen), Romania or the United Kingdom: a tax treaty exempts your benefits from U.S. tax.
- You repaid more benefits than you received this year: none of your benefits are taxable, and if the repayments are more than $3,000 above your benefits you may be able to take an itemized deduction or a credit for part of the excess.
Social Security tax on wages is a different tax
The Social Security tax taken from a paycheck is a payroll tax on earnings, not the income tax on benefits this calculator works out. Wages you earn while collecting benefits still owe it. The 2026 figures:
| 2026 payroll tax | Rate and limit |
|---|---|
| Social Security (OASDI) | 6.2% from the employee and 6.2% from the employer, on wages up to $184,500 |
| Medicare (HI) | 1.45% each from employee and employer, on all wages |
| Employee total | 7.65% |
| Self-employed | 15.30%: 12.4% Social Security up to $184,500, plus 2.9% Medicare |
| Maximum taxable earnings | $184,500 ($176,100 in 2025); no limit for Medicare |
| Additional Medicare tax | 0.9% on earned income over $250,000 married filing jointly, $125,000 married filing separately, $200,000 for everyone else |
From the Social Security Administration's 2026 cost-of-living adjustment fact sheet and its contribution and benefit base page, and IRS Topic 560 for the Additional Medicare Tax thresholds, checked September 27, 2026. At the limit, an employee pays $11,439 of Social Security tax for the year.
Sources
- IRS Publication 915: Social Security and equivalent railroad retirement benefits (Worksheet 1)
- 26 U.S.C. 86: Social Security and tier 1 railroad retirement benefits (base amounts)
- IRS: Instructions for Form 1040 (Social Security Benefits Worksheet, lines 6a and 6b)
- IRS: Schedule 1 (Form 1040), adjustments to income
- IRS: Rev. Proc. 2025-32 (2026 tax brackets and standard deduction)
- IRS: Deduction for seniors (FS-2025-03)
- Public Law 119-21, section 70103 (senior deduction)
- IRS Form W-4V: Voluntary withholding request
- IRS Publication 590-A: Contributions to IRAs (Roth conversions, IRA deduction worksheets)
- IRS Publication 590-B: Distributions from IRAs (Roth distributions)
- SSA: 2026 cost-of-living adjustment fact sheet (tax rates, maximum taxable earnings)
- SSA: Contribution and benefit base
- SSA: Request to withhold taxes (combined income)
- IRS Topic 560: Additional Medicare Tax
- IRS Tax Tip 2026-14: Filing season updates for seniors