Are Social Security benefits taxable at 100%?

No. Depending on your income (including tax-exempt interest) and your filing status, as much as 85% of Social Security benefits may be includible in gross income. If your income is lower, you may only have to include up to 50% or even no benefits at all in gross income. And 37 states don’t tax any portion of Social Security benefits. Of the other states with an income tax, most follow the federal rule.