Social Security Taxation Calculator

Legal basis: IRC §86 (taxation of Social Security benefits) · checked 2026-10-04 · Rates and limits change — verify the current figures.

Whether your Social Security benefits are taxed does not depend on how much you receive - it depends on how much other income you have. Under IRC Section 86, the test is provisional income: adjusted gross income computed without the benefits themselves, plus tax-exempt interest, plus one half of the annual benefits. If that total stays under the first base amount, none of your benefits are taxed. Above it, a growing share becomes taxable until the statutory ceiling of 85 percent of the benefit is reached.

The formula works in two bands. In the lower band - provisional income between the first and second base amounts - up to 50 percent of the excess over the first base, or 50 cents per dollar, is added to taxable income, capped at 85 percent of benefits. Above the second base amount, the inclusion is the larger of that lower-band amount and 85 percent of the excess over the second base, again capped at 85 percent of total benefits. In practice three outcomes exist: 0 percent, roughly 50 percent, and 85 percent of benefits taxed, with only a narrow transition zone between them.

The base amounts are statutory: $25,000 and $34,000 for single filers, $32,000 and $44,000 for married filing jointly. Unlike most dollar figures in the tax code they are not indexed for inflation, which is why the share of beneficiaries paying tax on benefits keeps drifting upward. Two details trip people up. Tax-exempt municipal bond interest counts even though it is not in AGI, and for married couples the income test is joint - a high-earning spouse can make a low-benefit spouse's benefits fully taxable.

Enter your annual benefit, your other taxable income, any tax-exempt interest, the base amounts for your filing status, and a marginal rate to estimate the actual tax. The calculator shows your provisional income, the taxable portion, the share of benefits taxed, and the estimated federal tax at your rate. Figures should be verified against current IRS rules, and state taxation of benefits, which varies by state, is not modeled here.

This calculator is an educational estimate, not tax or financial advice. Base amounts, brackets, and the treatment of benefits can change with legislation, and state taxation of benefits varies. Verify the current-year rules in IRS Publication 915 and confirm your situation with a CPA or fiduciary adviser.