SS Taxation
How to Calculate Combined Income for Social Security Benefits
Verified against SSA POMS as of September 16, 2026
The short answer
Combined income (also called provisional income) determines whether Social Security benefits are subject to federal income tax. It is calculated as AGI + tax-exempt interest + 50% of Social Security benefits. Single filers with provisional income above $25,000 and married couples above $32,000 may owe tax on up to 85% of their benefits depending on their income level.
The Combined Income Formula
Combined income (also called provisional income) is calculated as: Adjusted Gross Income (AGI) + Tax-Exempt Interest + 50% of Social Security benefits. This figure determines what percentage of Social Security benefits, if any, are subject to federal income tax. The income thresholds are fixed and not adjusted for inflation.
GN 05001.016Thresholds at a Glance
For single filers: below $25,000 = 0% taxable; $25,000–$34,000 = up to 50% taxable; above $34,000 = up to 85% taxable.
For married filing jointly: below $32,000 = 0%; $32,000–$44,000 = up to 50%; above $44,000 = up to 85%.
These thresholds have not changed since 1984 and 1993 respectively and are not indexed to inflation, meaning more retirees are affected each year.
GN 05001.016Income Included in Adjusted Gross Income (AGI)
AGI begins with taxable income from various sources and is reduced by certain adjustments to income. Common sources of income that may be included in AGI include:
- * Wages and self-employment income
- * Taxable interest and dividends
- * Capital gains
- * Taxable pension and annuity income
- * Taxable traditional IRA and retirement plan distributions
- * Rental and business income
- * Taxable Roth conversion amounts
Certain adjustments to income are then subtracted to arrive at AGI. AGI can be found on Form 1040, Line 11.
https://www.irs.gov/filing/adjusted-gross-incomeExample 1: Below the Threshold (0% Taxable)
Mary is single, receives $22,000 in Social Security benefits and has $14,000 in pension income with no tax-exempt interest. Her combined income is:
$14,000 + $11,000 (50% of Social Security) = $25,000
Mary's combined income is at the $25,000 threshold for single filers. Because her combined income does not exceed the threshold, none of her Social Security benefits are included in taxable income.
Example 2: In the 50% Zone
John is single, receives $24,000 in Social Security benefits and has $22,000 in IRA distributions. His combined income is:
$22,000 + $12,000 (50% of Social Security) = $34,000
His combined income falls within the $25,000–$34,000 range for single filers. The taxable portion of his Social Security benefits is calculated as:
($34,000 − $25,000) × 50% = $4,500
Therefore, $4,500 of John's $24,000 in Social Security benefits is included in taxable income, representing 18.75% of his total Social Security benefits.
Example 3: In the 85% Zone
Susan and David are married filing jointly. They receive $36,000 in Social Security benefits and have $50,000 in other income. Their combined income is:
$50,000 + $18,000 (50% of Social Security) = $68,000
Because their combined income exceeds the $44,000 upper threshold, the taxable portion of their Social Security benefits is calculated by adding:
- * $6,000, representing 50% of the $12,000 between the $32,000 and $44,000 thresholds; and
- * $20,400, representing 85% of the $24,000 that exceeds the $44,000 threshold.
$6,000 + $20,400 = $26,400
Therefore, $26,400 of their $36,000 in Social Security benefits is included in taxable income.
This example demonstrates an important point: being above the 85% threshold does not automatically mean that 85% of Social Security benefits will be taxable. In this case, $26,400—or about 73% of their benefits—is included in taxable income.
Frequently asked
Is the 50% or 85% refer to a tax rate?
No. It means that up to 50% or 85% of Social Security benefits may be included in taxable income. That amount is then taxed at the individual's applicable federal income tax rate.
Does everyone above the upper combined-income threshold automatically have 85% of their Social Security benefits included in taxable income?
No. Crossing the upper threshold means the 85% calculation applies, but it does not automatically make 85% of the entire Social Security benefit taxable. The actual taxable amount is determined by the applicable formula and cannot exceed 85% of total Social Security benefits.
Do qualified Roth IRA distributions increase combined income?
No. Qualified Roth IRA distributions are not included in gross income and therefore do not increase AGI or combined income. However, the taxable portion of a Roth conversion increases AGI and can increase combined income in the year of conversion.
Does tax-exempt municipal bond interest count toward combined income?
Yes. Tax-exempt interest is specifically added to AGI when calculating combined income, even though it may otherwise be exempt from federal income tax.