How to use this calculator
- Choose the tax year and the filing status you will use, and tick the age boxes that apply.
- Enter your Social Security benefits from box 5 of Form SSA-1099, adding your spouse's on a joint return.
- Enter your other taxable income as one figure: pensions, IRA and 401(k) withdrawals, wages, taxable interest and nonqualified dividends. A Roth conversion goes here too.
- Enter tax-exempt interest, such as municipal bond interest, and your qualified dividends and capital gains separately. Leave those out of other taxable income.
- Under More options, enter a deductible IRA contribution or similar adjustments, and your itemized deductions if you itemize.
The numbers already filled in are an example. Replace them with your own.
How it's calculated
The taxable part of your benefits comes from Worksheet 1 of IRS Publication 915, which applies section 86 of the tax code. It compares your provisional income with two thresholds: $25,000 and $34,000 for most filers, $32,000 and $44,000 on a joint return. Below the first, none of your benefits is taxable. Between the two, half of the income over the first threshold is taxable, up to half your benefits. Above the second, 85% of the income over it is added, and the total can never pass 85% of your benefits.
An example
Say you file single for 2026, you are 65 or older, your benefits are $24,000 and your other taxable income is $30,000. Your provisional income is half your benefits, $12,000, plus $30,000: $42,000. That is $17,000 over the $25,000 threshold. The first $9,000 of it makes $4,500 taxable, and the $8,000 above $34,000 makes 85% of that, $6,800, taxable too, for $11,300 in all (47.1% of your benefits).
Your adjusted gross income is then $30,000 plus $11,300, or $41,300. The standard deduction for a single filer 65 or older is $18,150, and the senior deduction adds $6,000, leaving $17,150 of taxable income and a federal income tax of $1,813. With none of your benefits taxable, the tax would be $588, so taxing your benefits costs you $1,225.
Why the next $1,000 can cost more than your bracket
While your benefits are still becoming taxable, an extra dollar of other income is taxed twice over: once itself, and again through the 50 or 85 cents of benefits it makes taxable. In the example, another $1,000 from an IRA makes $850 more of your benefits taxable and adds $222 of tax, a rate of 22.2% in the 12% tax bracket. Once 85% of your benefits is taxable, at $40,706 of other income here, the extra effect stops and your bracket rate applies again. The same thing happens to municipal bond interest: tax-free itself, but another $1,000 of it adds $102 of tax in the example.
The tax itself
The taxable part of your benefits joins your other income in adjusted gross income. The calculator then subtracts the larger of your standard or itemized deduction, the extra standard deduction for each person 65 or older or blind, and, for 2025 through 2028, the senior deduction: $6,000 for each person 65 or older, less 6% of income over $75,000 ($150,000 on a joint return), and not available on a separate return. Below $100,000 of taxable income the tax comes from the IRS Tax Table, and at $100,000 or more from the Tax Computation Worksheet. Qualified dividends and long-term gains are taxed at 0%, 15% or 20%, stacked on top of your ordinary income, as the IRS capital gains worksheet does.
Assumptions and limits
- Benefits are the net figure in box 5 of Form SSA-1099 (and RRB-1099 for railroad tier 1 benefits), for both spouses on a joint return. If box 5 is negative, none of your benefits are taxable; enter 0.
- Other taxable income is one figure with no losses. Enter a net capital loss as 0.
- The tax uses the IRS Tax Table below $100,000 of taxable income and the Tax Computation Worksheet at $100,000 or more, as the Form 1040 instructions require. The IRS prints each year's Tax Table with that year's instructions; for a year whose table is not out yet, the calculator applies the same rule to that year's published rates.
- Amounts are kept to the cent and the tax is rounded to the dollar. If you round every line of your return to whole dollars, your figures can differ by a dollar or two.
- "Tax caused by your benefits" is your tax less the tax you would owe if none of your benefits were taxable, with everything else the same, including the senior deduction recomputed.
- The senior deduction assumes each person counted has a valid Social Security number. You count as 65 for a tax year if you were born before January 2 of the year 64 years earlier (for 2025, before January 2, 1961), because the IRS treats you as 65 on the day before your 65th birthday.
- The tax is federal income tax before credits. It does not include the net investment income tax, the alternative minimum tax, self-employment tax, or state income tax.
- It does not model the lump-sum election for benefits paid for earlier years, the foreign earned income and savings bond exclusions, the 2025 to 2028 deductions for tips, overtime and car loan interest, the qualified business income deduction, or a spouse's age or blindness on a separate return. On a separate return, if your spouse itemizes you must too.
Input field details
What to enter in each box, where to find the number, and how this calculator treats it. When two calculators give different answers from the same numbers, it's usually because they handle one of these differently.
Filing status
The status you will file under for the tax year.
How this tool treats itBenefits start to be taxable above $25,000 of provisional income, or $32,000 on a joint return. On a separate return, if you and your spouse lived together at any time in the year, that threshold is $0, so up to 85% of your benefits can be taxable from the first dollar. A qualifying surviving spouse uses the joint tax rates and standard deduction but the $25,000 threshold.
65 or older
Tick it if you were born before January 2 of the year 64 years before the tax year (for 2025, before January 2, 1961). On a joint return, tick your spouse’s too if it applies.
How this tool treats itThe IRS treats you as reaching 65 on the day before your 65th birthday, which is why someone born on January 1 counts for the year before. Each tick adds to your standard deduction, and for 2025 through 2028 also gives a $6,000 senior deduction that shrinks by 6% of income over $75,000, or $150,000 on a joint return. The senior deduction is not allowed on a separate return.
Not includedOn a separate return, your spouse’s age counts toward your standard deduction only if your spouse had no income and is nobody’s dependent. This calculator does not count it. Someone born in time who died during the year before reaching 65 does not count.
Social Security benefits
Your net benefits for the year. On a joint return, add your spouse’s.
Where to find itBox 5 of Form SSA-1099, which Social Security mails each January. For railroad retirement, add box 5 of Form RRB-1099.
How this tool treats itBox 5 is after any repayments. If it shows a negative number, none of your benefits are taxable; enter 0.
Allowed range$0 to $200,000
Not includedA lump-sum payment covering earlier years can be figured a second way that may lower the taxable amount (Publication 915, Worksheets 2 to 4). This calculator uses the ordinary method.
Other taxable income
Everything taxable except your benefits and the qualified dividends and net capital gain you enter separately: pensions, IRA and 401(k) withdrawals, wages, taxable interest, nonqualified dividends and net short-term gains.
Where to find itForm 1040 lines 1z, 2b, 4b and 5b, Schedule 1 line 10, and nonqualified dividends (Form 1099-DIV box 1a minus box 1b).
How this tool treats itA Roth conversion goes here; a tax-free Roth IRA withdrawal does not. A qualified charitable distribution from an IRA is not income and does not go here.
Allowed range$0 to $5,000,000
Not includedLosses. Enter a net loss as 0.
Tax-exempt interest
Interest that is not taxed, such as interest on municipal bonds.
Where to find itForm 1040 line 2a, or box 8 of Form 1099-INT.
How this tool treats itIt is not taxed itself, but half of your benefits plus your other income plus this interest is your provisional income, so it can make more of your benefits taxable.
Allowed range$0 to $1,000,000
Qualified dividends and capital gains
Qualified dividends plus your net capital gain. Leave them out of other taxable income.
Where to find itQualified dividends are Form 1099-DIV box 1b (Form 1040 line 3a). Net capital gain is your capital gain distributions (1099-DIV box 2a) if you do not file Schedule D, or the smaller of Schedule D lines 15 and 16 if you do.
How this tool treats itThese are taxed at 0%, 15% or 20%, stacked on top of your ordinary income, so a larger taxable Social Security amount can push them out of the 0% band.
Allowed range$0 to $5,000,000
Not includedCollectibles gains and unrecaptured section 1250 gain are taxed at up to 28% and 25%; here they would be taxed at 0%, 15% or 20%, which understates the tax. A net capital loss is entered as 0, which overstates it.
Blind
Tick it if you are blind at the end of the year. On a joint return, tick your spouse’s too if it applies.
How this tool treats itBlind here means vision no better than 20/200 in the better eye with glasses or contacts, or a field of vision of 20 degrees or less. Each tick adds to the standard deduction.
Adjustments to income
Deductions you take before AGI: a deductible IRA contribution, HSA contributions, half of self-employment tax, self-employed retirement contributions and health insurance, alimony paid under a pre-2019 agreement.
Where to find itSchedule 1 (Form 1040), lines 11 through 20, 23 and 25.
How this tool treats itLeave out the student loan interest deduction. The Social Security worksheet adds it back, so it does not lower your provisional income.
Allowed range$0 to $1,000,000
Not includedIf you or your spouse is covered by a retirement plan at work, how much of a traditional IRA contribution you can deduct depends on income that includes your taxable benefits. Work that deduction out first with IRS Publication 590-A, then enter it here.
Itemized deductions
Your total itemized deductions, if you itemize. Leave it at 0 to use the standard deduction.
Where to find itSchedule A (Form 1040), line 17.
How this tool treats itThe calculator uses whichever is larger, your itemized total or your standard deduction. Neither changes how much of your benefits is taxable, because both are subtracted after AGI.
Allowed range$0 to $5,000,000
Not includedOn a separate return, if your spouse itemizes you must too. Enter your itemized deductions in that case.
Questions
Is this the Social Security payroll tax?
How much of my Social Security is taxable?
What is provisional income?
Does "85% taxable" mean an 85% tax?
Did the 2025 tax law stop taxing Social Security?
Why don't the $25,000 and $32,000 thresholds rise with inflation?
Does municipal bond interest count?
What if we file separately?
Version history
- September 24, 2026 (version 1.0.0): First version. Finds the taxable part of your Social Security with the IRS worksheet, the federal tax it causes, and what the next $1,000 of income would cost, for 2025 and 2026.