26 U.S.C. § 86
§ 86. Social security and tier 1 railroad retirement benefits
Explainer
When Social Security benefits are taxed
Between 0% and 85% of Social Security benefits are taxable, depending on “combined income” — and the $25,000 / $32,000 thresholds haven't changed since they were set in 1983.
In plain English
Social Security benefits are partly taxable for many retirees. Section 86 uses a measure called provisional income (often called "combined income"): half your benefits, plus all your other income, plus any tax-exempt interest.
| Provisional income (single) | Provisional income (joint) | Share of benefits taxed |
|---|---|---|
| Up to $25,000 | Up to $32,000 | 0% |
| $25,000 – $34,000 | $32,000 – $44,000 | up to 50% |
| Over $34,000 | Over $44,000 | up to 85% |
The share is never more than 85%. "Up to" matters: the formula phases in, so crossing a line doesn't suddenly make 50% or 85% of everything taxable.
Who it touches
Tens of millions of retirees, disabled workers and survivors receive Social Security. Those with pensions, IRA withdrawals, part-time work or investment income are the ones most likely to pay tax on part of it.
The numbers that never moved
The $25,000 and $32,000 thresholds were set in 1983, and the $34,000 / $44,000 tier was added in 1993. Neither is adjusted for inflation. Benefits do rise with inflation each year, so more retirees cross the lines over time without their real income changing.
From 2025 through 2028, people aged 65 or older can also take an extra $6,000 deduction each ($12,000 for a couple), which phases out above $75,000 of income ($150,000 joint). It doesn't change how much of the benefit is taxable, but it lowers the tax on it.
Worked example
Helen is single and receives $24,000 of Social Security plus a $20,000 pension.
- Provisional income: $12,000 (half of benefits) + $20,000 = $32,000
- That's $7,000 over the $25,000 base, but still under $34,000
- Taxable benefits: half of $7,000 = $3,500 (capped at half of benefits, $12,000)
So $3,500 of her $24,000 in benefits is added to her taxable income.
Watch out for
- Tax-exempt municipal bond interest counts toward provisional income, so it can make benefits taxable.
- Married filing separately while living together: the threshold is $0, so up to 85% is taxable from the first dollar.
- You can ask Social Security to withhold federal tax from benefits with Form W-4V, at 7%, 10%, 12% or 22%.
Draft explainer. Figures checked against IRS Rev. Proc. 2025-32 and the current text on November 4, 2026. Not yet reviewed by a licensed tax professional.
Sources
The law as written
Current through Public Law 119-102. Amendment notes omitted.
Structure
Except as provided in paragraph (2), gross income for the taxable year of any taxpayer described in subsection (b) (notwithstanding section 207 of the Social Security Act) includes social security benefits in an amount equal to the lesser of—
one-half of the social security benefits received during the taxable year, or
one-half of the excess described in subsection (b)(1).
In the case of a taxpayer with respect to whom the amount determined under subsection (b)(1)(A) exceeds the adjusted base amount, the amount included in gross income under this section shall be equal to the lesser of—
the sum of—
85 percent of such excess, plus
the lesser of the amount determined under paragraph (1) or an amount equal to one-half of the difference between the adjusted base amount and the base amount of the taxpayer, or
85 percent of the social security benefits received during the taxable year.
A taxpayer is described in this subsection if—
the sum of—
the modified adjusted gross income of the taxpayer for the taxable year, plus
one-half of the social security benefits received during the taxable year, exceeds
the base amount.
For purposes of this subsection, the term “modified adjusted gross income” means adjusted gross income—
determined without regard to this section and sections 85(c), 135, 137, 221, 911, 931, and 933, and
increased by the amount of interest received or accrued by the taxpayer during the taxable year which is exempt from tax.
For purposes of this section—
The term “base amount” means—
except as otherwise provided in this paragraph, $25,000,
$32,000 in the case of a joint return, and
zero in the case of a taxpayer who—
is married as of the close of the taxable year (within the meaning of section 7703) but does not file a joint return for such year, and
does not live apart from his spouse at all times during the taxable year.
The term “adjusted base amount” means—
except as otherwise provided in this paragraph, $34,000,
$44,000 in the case of a joint return, and
zero in the case of a taxpayer described in paragraph (1)(C).
For purposes of this section, the term “social security benefit” means any amount received by the taxpayer by reason of entitlement to—
a monthly benefit under title II of the Social Security Act, or
a tier 1 railroad retirement benefit.
For purposes of this section, the amount of social security benefits received during any taxable year shall be reduced by any repayment made by the taxpayer during the taxable year of a social security benefit previously received by the taxpayer (whether or not such benefit was received during the taxable year).
If (but for this subparagraph) any portion of the repayments referred to in subparagraph (A) would have been allowable as a deduction for the taxable year under section 165, such portion shall be allowable as a deduction only to the extent it exceeds the social security benefits received by the taxpayer during the taxable year (and not repaid during such taxable year).
For purposes of this section, if, by reason of section 224 of the Social Security Act (or by reason of section 3(a)(1) of the Railroad Retirement Act of 1974), any social security benefit is reduced by reason of the receipt of a benefit under a workmen’s compensation act, the term “social security benefit” includes that portion of such benefit received under the workmen’s compensation act which equals such reduction.
For purposes of paragraph (1), the term “tier 1 railroad retirement benefit” means—
the amount of the annuity under the Railroad Retirement Act of 1974 equal to the amount of the benefit to which the taxpayer would have been entitled under the Social Security Act if all of the service after December 31, 1936, of the employee (on whose employment record the annuity is being paid) had been included in the term “employment” as defined in the Social Security Act, and
a monthly annuity amount under section 3(f)(3) of the Railroad Retirement Act of 1974.
For purposes of subsection (a), in any case where section 708 of the Social Security Act causes social security benefit checks to be delivered before the end of the calendar month for which they are issued, the benefits involved shall be deemed to have been received in the succeeding calendar month.
If—
any portion of a lump-sum payment of social security benefits received during the taxable year is attributable to prior taxable years, and
the taxpayer makes an election under this subsection for the taxable year,
then the amount included in gross income under this section for the taxable year by reason of the receipt of such portion shall not exceed the sum of the increases in gross income under this chapter for prior taxable years which would result solely from taking into account such portion in the taxable years to which it is attributable.
For purposes of this subsection, a social security benefit is attributable to a taxable year if the generally applicable payment date for such benefit occurred during such taxable year.
An election under this subsection shall be made at such time and in such manner as the Secretary shall by regulations prescribe. Such election, once made, may be revoked only with the consent of the Secretary.
For purposes of—
section 22(c)(3)(A) (relating to reduction for amounts received as pension or annuity),
section 32(c)(2) (defining earned income),
section 219(f)(1) (defining compensation), and
section 911(b)(1) (defining foreign earned income),
any social security benefit shall be treated as an amount received as a pension or annuity.