Taxable Social Security Calculator: How Much of Your Benefit Is Taxed?

Sometimes, and for most retirees with savings, yes. Federal income tax applies to part of your Social Security when your other income is high enough. Nothing is taxable if your provisional income is at or below $25,000 on a single return or $32,000 on a joint return. Above that, up to half of your benefits can be taxed, and above $34,000 single or $44,000 joint, up to 85%. No one is taxed on more than 85% of their benefits, however high their income (IRS Publication 915; IRS Topic 423).

“85% taxable” does not mean an 85% tax rate. It means up to 85% of your benefits is added to your taxable income, where it is taxed at your ordinary rates like a pension. A couple in the 12% bracket with 85% of their benefits taxable pays roughly 10% of their Social Security in federal tax, not 85%.

Illustrative example: the people and figures below are hypothetical, not real clients. Numbers are calculated from the stated assumptions.

Two couples show the range. One, both retired, collects $36,000 a year of Social Security and has $10,000 of pension and $1,000 of interest. Their provisional income is $29,000, under the $32,000joint base amount, so none of their benefits is taxed. The calculator's example couple, Frank (71) and Carol (68), collect $4,800 a month, $57,600 a year, and have $44,000 of pension, IRA withdrawals, interest and dividends. $32,180 of their benefits is taxable, 55.9% of the total, and their federal tax for 2026 is $2,468.

The test uses a measure that appears nowhere else on your return. Social Security calls it “combined income”, and planners call it provisional income. It is:

• half of your Social Security benefitsfor the year (both spouses' on a joint return), using the gross amount before Medicare premiums are taken out;
• plus all your other income that is on the return: wages, pensions, traditional IRA and 401(k) withdrawals including RMDs and Roth conversions, taxable interest, dividends and net capital gains;
• plus tax-exempt interest, mainly from municipal bonds, even though it is not otherwise taxed.

Some money stays out. Qualified withdrawals from a Roth IRA, qualified charitable distributions sent straight from an IRA to charity, HSA withdrawals for medical costs, the return of your own basis when you sell investments, and cash taken from savings are not income, so they do not count. Above-the-line deductions on Schedule 1, such as a deductible IRA contribution, reduce it.

For Frank and Carol: half of $57,600 is $28,800; their other income is $44,000; their municipal bond interest is $2,000. Provisional income is $74,800, well above the $44,000 threshold where the 85% formula begins. Because only half of benefits counts, a couple can have a large Social Security income and still owe nothing on it; it is the other income on top that decides.

There are two thresholds for each filing status. Head of household and qualifying surviving spouse returns use the single figures.

The first pair, $25,000 and $32,000, was set by the Social Security Amendments of 1983, when benefits were first taxed, starting with 1984. The second, $34,000 and $44,000, was added in 1993 and applied from 1994. Unlike tax brackets, the standard deduction and the IRMAA thresholds, neither pair has ever been indexed to inflation. Congress set them so that only higher-income retirees would pay; inflation has done the rest.

Had the thresholds kept pace with consumer prices, the $32,000 joint base amount from 1984 would be about $99,155 in 2025 dollars, and the $44,000 figure from 1994 about $95,584. The single base amount would be about $77,465. Because benefits rise each year with the cost-of-living adjustment (2.8% for 2026, per the SSA fact sheet) while the thresholds stay put, a retiree whose real income never changes has a little more of their benefit taxed each year. What was designed as a tax on the well-off now reaches many middle-income retirees with a modest IRA.

The formula works in two layers. Between the first and second thresholds, each dollar of provisional income above the base amount makes 50 cents of benefits taxable. Above the second threshold, each dollar makes 85 cents taxable, on top of the amount from the first layer. Two caps apply: the first layer can never exceed half your benefits, and the total can never exceed 85% of them. Once you hit the 85% cap, more income makes no more of your benefits taxable.

The labels “50% band” and “85% band” describe the most that can be taxed, not what is. Frank and Carol are well into the 85% band, yet only 55.9% of their benefits is taxable, because the amount builds up gradually from the threshold. Here is their calculation, using the same lines as Worksheet 1 in Publication 915:

Line 15 is the first layer, capped at $6,000: half of the $12,000 band between the thresholds. Line 16 is the second layer: 85% of the $30,800 of provisional income above $44,000. Their total, $32,180, is below the $48,960 cap on line 18, so it is the taxable amount that goes on line 6b of Form 1040.

Between the point where benefits start to be taxed and the point where the 85% cap is reached, every extra dollar of income does two things: it is taxed itself, and it drags 50 or 85 cents of Social Security into taxable income with it. A dollar that should be taxed at 12% is taxed as $1.85 of income, an effective rate of about 22.2%. In the 22% bracket the same dollar costs about 41 cents. Planners call this stretch of income the tax torpedo. It is not in the tax tables, so many retirees in it do not know they are paying it.

Illustrative example: the people and figures below are hypothetical, not real clients. Numbers are calculated from the stated assumptions.

Frank and Carol are in it. Their taxable income is $28,680, in the 12% bracket. Another $1,000 from their IRA adds $220 of federal tax, an effective rate of 22.0%, because it also makes $850 more of their Social Security taxable. Taking an extra $10,000 would cost $2,218. The torpedo lasts for about $19,741 more of IRA withdrawals; after that, 85% of their benefits is taxable and extra income is taxed at the bracket rate again.

The torpedo bites harder for single filers, whose thresholds are lower and whose brackets are narrower. A single retiree of 72 with $50,400 of Social Security and $44,000 of pension, IRA and investment income is in the 22% bracket with 68.3% of benefits taxable. The next $1,000 costs her $431, a 43.1% rate, because the extra income is also phasing out her senior deduction (more on that below). That is more than the top 37% bracket, on an AGI of $78,420.

The chart in the calculator shows other bumps too. Further up, extra ordinary income can push qualified dividends and long-term gains out of the 0% rate, adding 15 cents per dollar for a while; and the senior deduction's phase-out adds a few points across a wide range. The calculator reruns the whole return at each step, so all of these show up in the effective rate. If much of your income comes from a stock portfolio, the dividend calculator shows how dividends make Social Security taxable.

The tax law enacted in July 2025, the One Big Beautiful Bill Act, was promoted as ending tax on Social Security. It did not change how benefits are taxed. The provisional income formula, the $32,000 and $44,000 thresholds and the 85% cap are exactly as they were, and line 6b of Form 1040 is figured the same way.

What the law added is a temporary deduction for older taxpayers (IRS). For 2025 through 2028, each person who is 65 or older by the end of the year can deduct $6,000, $12,000 for a married couple who both qualify. It is on top of the standard deduction and the existing extra standard deduction for those 65 and over ($1,650 per spouse on a joint return, $2,050 for a single filer, in 2026), and it is available whether you itemize or not. It phases out by 6% of modified adjusted gross income above $75,000 for single filers and $150,000 for joint filers, per qualifying person. A married couple must file jointly to claim it, and each person needs a Social Security number on the return.

Three consequences are easy to miss:

• It lowers taxable income, not taxable benefits. For Frank and Carol it is worth $12,000 of deduction, about $1,438 of tax at their rates. Their taxable Social Security is still $32,180, and the torpedo still runs at 22.0%.
• It depends on age, not on Social Security. Someone who claimed at 62 gets nothing from it until 65; someone of 66 who is delaying benefits gets it in full.
• Its phase-out stacks with the torpedo. MAGI for the phase-out includes taxable Social Security, so each extra IRA dollar in the torpedo raises it by up to $1.85 and cuts the deduction by 6% of that. That is part of why the single retiree above pays 43.1% on her next dollar.

Unless Congress extends it, the deduction ends after 2028. From 2029 the same household would have more taxable income on the same benefits.

Most of these work by lowering provisional income, or by moving income into years when the torpedo is not running. Each figure below reruns the calculator on Frank and Carol with one thing changed.

Roth conversions before you claim

Qualified Roth IRA withdrawals do not count in provisional income. If the $24,000 Frank and Carol take from traditional IRAs each year came from a Roth instead, their taxable benefits would fall to $11,780 and their federal tax to $0, a saving of $2,468 a year. The cheapest time to build that Roth is in the years after you stop work and before you claim Social Security: conversions then are taxed at your bracket rate with no benefits to pull into tax. Converting after you claim can still pay off, but each converted dollar inside the torpedo zone is taxed at the higher effective rate. Our guide to Roth conversions before RMDs covers the sizing, and the Roth IRA calculator projects the account. The Roth conversion calculator shows how much to convert before benefits start, year by year.

Time your IRA withdrawals

Because each tax year is figured separately, the same total withdrawal can cost different amounts depending on how it is spread. Frank and Carol taking $24,000 in each of two years pay $4,936 of federal tax over the two years. Taking nothing one year and $48,000 the next costs $7,359, so for them, spreading wins by $2,423. For households already above the torpedo, bunching can sometimes win instead. Run both years in the calculator before deciding, and keep the rest of your plan, including RMDs once they start, in view.

Give through qualified charitable distributions

From 70½ you can send up to $111,000 a year (2026) directly from an IRA to charity (IRS Publication 590-B). The distribution never reaches your income, so it lowers provisional income dollar for dollar, and once RMDs begin it counts toward them. If Frank and Carol replaced $10,000 of their IRA withdrawals with a $10,000 QCD, their taxable benefits would drop by $8,500 and their federal tax by $1,850. A check written from checking does not do this, even if you itemize. See qualified charitable distributions.

Municipal bond interest still counts

Tax-exempt interest is added back into provisional income, so moving taxable bonds into municipal bonds saves the tax on the interest itself but does nothing for your Social Security. If Frank and Carol swapped their $3,000 of taxable interest for the same amount of municipal interest, their taxable benefits would stay at $32,180, and they would save $300, only the tax on the interest. Munis can still make sense after accounting for their lower yields, and the bond calculator shows the tax-equivalent yield of a muni at your bracket; just do not count on them to escape the torpedo.

Delay claiming Social Security

Waiting to claim, up to 70, does two things for tax. It opens the years before claiming for withdrawals and Roth conversions at plain bracket rates, and it shifts your retirement income toward Social Security, which is at most 85% taxable, and away from IRA withdrawals, which are fully taxable. A larger benefit can push more of it into tax later, but each extra dollar of benefit adds only 50 cents to provisional income. Our guide on when to claim Social Security weighs the trade-offs, and the Social Security estimator shows the benefit at each age.

Social Security does not withhold income tax unless you ask. You can file Form W-4V with Social Security to have 7%, 10%, 12% or 22% of each payment withheld; no other percentages are allowed (IRS, Form W-4V; SSA). The alternatives are quarterly estimated payments on Form 1040-ES, or extra withholding from a pension or IRA distribution. Withholding from an IRA distribution has one advantage: it counts as paid evenly through the year even if taken in December, which can cure an underpayment late in the year.

For Frank and Carol, federal tax of $2,468 is 4.3% of their benefits. Withholding at the lowest W-4V rate, 7%, from both checks would collect $4,032, more than they owe, so withholding a set amount from the IRA withdrawals, or a December payment, would match their bill more closely.

Most states with an income tax exempt Social Security benefits, and states without an income tax do not tax them at all. A small and shrinking number of states still tax some benefits, usually with their own income-based exemptions or credits that spare many retirees, and several have repealed their tax in recent years. The rules change often, so check your state revenue department's current guidance or ask your preparer. This calculator covers federal tax only.

Medicare's income-related premium surcharge, IRMAA, uses modified adjusted gross income: your AGI, which includes the taxable part of your Social Security, plus tax-exempt interest. It does not use provisional income. For Frank and Carol, provisional income is $74,800 while their MAGI for IRMAA is $78,180. The two measures move together, because extra IRA income raises both, but IRMAA works in cliffs and looks back two years. The IRMAA calculator shows how far you are from the next tier. The marginal rates on this page do not include IRMAA.

For how this fits with the rest of your tax picture in retirement, including RMDs and capital gains, see taxes in retirement.

• Married filing separately. If you lived with your spouse at any time in the year, the base amount is zero and up to 85% of benefits is taxable from the first dollar. It is rarely chosen for that reason, and the calculator does not model it.
• Adjustments and lump sums. Schedule 1 adjustments, such as a deductible IRA contribution, lower provisional income; the calculator does not collect them. A lump-sum benefit payment for earlier years can be taxed under a special election in Publication 915 that it does not apply.
• Credits, state tax and IRMAA. Federal tax here is income tax plus the net investment income tax, with no credits. State tax and Medicare surcharges are not included.