Federal Tax Thresholds and Phase-Outs for Social Security

Federal tax on Social Security benefits kicks in once your combined income passes fixed dollar thresholds set by statute. If you file as an individual and your combined income tops $25,000, up to half of your benefits can be taxed; above $34,000, up to 85% can. For married couples filing jointly, the same tiers begin at $32,000 and $34,000 (up to 50%) and $44,000 (up to 85%). These are the federal tax thresholds for Social Security benefits, and they have not been adjusted for inflation since Congress set them in 1983.¹

How Combined Income Is Calculated

You cannot apply the thresholds without first working out your combined income. The formula has three parts:

Your adjusted gross income (AGI) from your tax return, which includes wages, pensions, investment income, and traditional retirement account withdrawals.
Any tax-exempt interest, such as interest from municipal bonds. This normally escapes taxation but gets added back for this calculation.
One-half of the Social Security benefits you received during the year.

Add the three and you have your combined income. So if your AGI is $20,000, you received $1,000 in municipal bond interest, and Social Security paid you $12,000, your combined income is $27,000. The controlling statute, 26 U.S.C. § 86, calls the AGI-plus-tax-exempt-interest piece “modified adjusted gross income.”¹

Some income never enters this calculation. Qualified withdrawals from a Roth IRA or Roth 401(k) do not appear in AGI, so they do not push you toward the thresholds. Life insurance death benefits you receive as a beneficiary are also excluded from gross income, although any interest earned on those proceeds does count.²

The Thresholds by Filing Status

Single, Head of Household, or Qualifying Surviving Spouse

Combined income under $25,000: none of your benefits are taxable.
Combined income between $25,000 and $34,000: up to 50% of your benefits may be taxable.
Combined income above $34,000: up to 85% of your benefits may be taxable.

Married Filing Jointly

Combined income under $32,000: none of your benefits are taxable.
Combined income between $32,000 and $44,000: up to 50% of benefits may be taxable.
Combined income above $44,000: up to 85% of benefits may be taxable.¹

Married Filing Separately

Married couples who file separately and lived together at any point during the year get the harshest treatment. Their base amount is $0, so virtually all benefits become subject to tax regardless of income level. The rule exists to keep couples from splitting returns purely to avoid the tax. If you filed separately but genuinely lived apart from your spouse for the entire year, the regular $25,000 and $34,000 individual thresholds apply instead.¹

What the 50% and 85% Figures Actually Mean

These percentages trip people up. They do not represent tax rates on your benefits. They tell you how much of your benefit amount is added to your other income, which is then taxed at your regular marginal rate. If you are in the 12% bracket and 50% of your benefits are taxable, the effective federal tax rate on those benefits is 6%.

The statute also caps the taxable share at 85% of your total annual benefits no matter how high your income goes. At least 15% of your benefit always stays untaxed.¹

The math compares two figures and uses the smaller one. In the 50% tier, the IRS looks at either half of your benefits or half of the amount by which your combined income exceeds the base threshold, and taxes the lower figure. In the 85% tier, an additional calculation layers 85% of the excess over the higher threshold onto the amount from the first tier. IRS Publication 915 provides worksheets that walk through the full computation, and most tax software handles it automatically.³

The Tax Torpedo in the Phase-In Range

Inside the phase-in ranges, the thresholds do something most retirees never expect. Every additional dollar of ordinary income in the 50% tier causes another $0.50 of your Social Security benefits to become taxable. So a single dollar of pension income effectively creates $1.50 of taxable income: the dollar itself plus $0.50 of newly taxable benefits. A retiree in the 12% federal bracket faces an effective marginal rate of 18% through that range.

It gets worse in the 85% zone. Each extra dollar of income there pulls $0.85 of benefits into taxable income, producing $1.85 in taxable income per dollar earned. Someone in the 22% bracket experiences an effective marginal rate of about 40.7% while moving through that range. Financial planners call this the tax torpedo, and it hits middle-income retirees the hardest because they sit squarely in the phase-in zone. Once all 85% of benefits are already taxable, the effect disappears and rates return to the ordinary bracket.

SSDI Follows These Rules; SSI Does Not

Social Security Disability Insurance (SSDI) benefits follow the same combined income thresholds and tiers described above. Supplemental Security Income (SSI), a needs-based program, is completely exempt from federal income tax and is never included in taxable income.⁴

The 2025–2028 Senior Deduction Did Not Repeal This Tax

There has been widespread confusion about whether recent legislation eliminated tax on Social Security benefits. It did not. The One, Big, Beautiful Bill Act left the taxation rules under Section 86 fully intact. What it created is a separate deduction for taxpayers age 65 and older: up to $6,000 per qualifying person, or $12,000 for married couples filing jointly when both spouses qualify, for tax years 2025 through 2028. The deduction is available whether you itemize or take the standard deduction.⁵

It phases out for single filers with modified adjusted gross income above $75,000 and joint filers above $150,000, disappearing entirely at $175,000 and $250,000. Lower-income retirees who qualify for the full amount see a meaningful reduction in total taxable income, which indirectly reduces the tax owed on the taxable portion of benefits. But the deduction does not change how much of your benefits become taxable. The combined income thresholds, the 50% and 85% tiers, and the 85% cap all remain unchanged.⁵

Ways to Keep Combined Income Below the Thresholds

Because the thresholds depend on combined income, anything that lowers your AGI also lowers the taxable share of your benefits.

Roth conversions completed before you claim benefits can pay off substantially. Qualified withdrawals from a Roth account do not appear in AGI at all, keeping combined income lower throughout retirement. The trade-off is paying tax on the converted amount up front, which works best during low-income years before Social Security or required minimum distributions begin.

If you are 70½ or older and take required minimum distributions from a traditional IRA, qualified charitable distributions let you send up to $111,000 per person directly from the IRA to a qualified charity in 2026. The donated amount satisfies your distribution requirement without appearing in AGI, which can keep combined income under the base thresholds.⁶

Timing helps too. Retirees who can control when to sell investments or take retirement account withdrawals sometimes bunch income into alternating years, staying under the $25,000 or $32,000 base in the off years. Because of the torpedo effect, that kind of planning is worth more than it looks.

State Taxation Is a Separate Question

Federal thresholds are only part of the picture. Nine states also tax Social Security benefits to varying degrees: Colorado, Connecticut, Minnesota, Montana, New Mexico, Rhode Island, Utah, Vermont, and West Virginia. Most use their own income thresholds or age-based exemptions, and the rules change frequently. West Virginia, for example, is making benefits fully deductible starting in 2026. If you live in one of these states, check your state’s current rules separately, because they differ significantly from the federal system.

Why More Retirees Cross the Threshold Every Year

The revenue from taxing Social Security benefits flows back into the Social Security Trust Funds, not the general treasury. That was a deliberate choice when Congress added the tax through the 1983 amendments to shore up the program’s finances.⁷ But leaving the thresholds frozen has had a compounding effect. In 1984, the $25,000 base was high enough that only about 10% of beneficiaries owed any tax on their benefits. Today, because the thresholds never moved while wages and benefit amounts grew with inflation, roughly half of all Social Security households pay some federal tax on their benefits. Unless Congress indexes these thresholds, the share will keep growing.

1
Office of the Law Revision Counsel. 26 USC 86 – Social Security and Tier 1 Railroad Retirement Benefits
2
Internal Revenue Service. Life Insurance and Disability Insurance Proceeds
3
Internal Revenue Service. Publication 915 (2025), Social Security and Equivalent Railroad Retirement Benefits
4
Internal Revenue Service. Regular and Disability Benefits
5
Internal Revenue Service. 2026 Filing Season Updates and Resources for Seniors
6
Congressional Research Service. Qualified Charitable Distributions From Individual Retirement Accounts
7
Social Security Administration. Taxation of Social Security Benefits – 1983 Amendments