Updated July 23, 2026. Quick answer: Provisional income (the IRS calls it combined income) is your adjusted gross income excluding Social Security, plus tax-exempt interest, plus half of your annual Social Security benefit. It decides how much of your benefit is taxable: none below the base threshold, up to 50% in the middle band, and up to 85% above the upper threshold. The thresholds are fixed by law and are not inflation-adjusted — $25,000/$34,000 for single filers and $32,000/$44,000 for joint filers — which is why more retirees cross them every year. Use the calculator below to see your number in dollars.
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Provisional income calculator
How to calculate provisional income (the formula)
Provisional income = AGI (excluding Social Security) + tax-exempt interest + 50% of your annual Social Security benefit. Note that tax-exempt municipal bond interest counts even though it is not taxed — a common surprise. The IRS walks through the same math in Publication 915, and the SSA summarizes the thresholds on its benefits-taxation page.
Provisional income thresholds by filing status
| Filing status | 0% band | Up-to-50% band | Up-to-85% band |
|---|---|---|---|
| Single, head of household, qualifying surviving spouse | Under $25,000 | $25,000–$34,000 | Over $34,000 |
| Married filing jointly | Under $32,000 | $32,000–$44,000 | Over $44,000 |
| Married filing separately (lived apart all year) | Under $25,000 | $25,000–$34,000 | Over $34,000 |
| Married filing separately (lived together) | — | — | From the first dollar |
These thresholds have been fixed since the 1980s and 1990s and do not adjust for inflation, so ordinary cost-of-living increases push more retirees into the taxable bands each year.
What moves provisional income (and what doesn’t)
Traditional IRA and 401(k) withdrawals, capital gains, dividends, interest, and rental income all raise provisional income. Qualified Roth withdrawals do not, and qualified charitable distributions (QCDs) from an IRA satisfy RMDs without landing in AGI. That is why withdrawal sequencing matters: coordinating which accounts you draw first can change both this calculation and your Medicare premiums — see retirement tax windows and the IRMAA brackets guide, and sanity-check the taxable result with the Social Security taxability calculator. An advisor who plans withdrawals around these lines should show the work in dollars — compare what that planning costs with the Financial Advisor Fee Calculator.
Want the withdrawal plan, not just the number?
Sequencing withdrawals around the provisional-income and IRMAA lines is exactly the kind of work a fee-transparent fiduciary should put in writing, with the tax math shown.
This is the number that makes withdrawal ORDER a tax decision.
How much of your Social Security is taxable depends on income you partly control, which means sequencing accounts changes the answer. The advisers below pay to meet people at that question. It is free to you, and it is not the only way to find an adviser.
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Methodology
This page was materially reviewed on July 23, 2026. The calculator implements the federal provisional-income (combined-income) formula and statutory thresholds described in IRS Publication 915; it is educational, ignores state taxation of benefits, and is not personalized financial, tax, legal, or investment advice. See our Editorial Policy, Corrections, Affiliate Disclosure, and Disclaimer.