Is your Social Security taxable? How the 50% and 85% rules work

Provisional income: the number that decides it

The IRS does not tax your Social Security by looking at the benefit alone. It looks at provisional income:

Provisional income = your other income + any tax-exempt interest + half of your Social Security benefits

"Other income" means things like pensions, wages, interest, dividends, and withdrawals from a traditional 401(k) or IRA, including Roth conversions.

The thresholds

These thresholds were set decades ago and are not adjusted for inflation. Each year, more households cross them. The most that can ever be taxable is 85% of your benefit. Never 100%.

A worked example

A married couple files jointly. They have $40,000 of other income and $24,000 a year in Social Security.

1. Half of their benefits is $12,000.
2. Provisional income is $40,000 + $12,000 = $52,000. That is over $44,000, so the 85% tier applies.
3. The taxable part of their benefit works out to $12,800. That is $6,800 from the 85% tier plus $6,000 from the 50% tier. It is about 53% of their benefits, and it stays under the 85% cap of $20,400.

That $12,800 is added to their other income and taxed at their ordinary rates, after the standard deduction ($32,200 for a married couple in 2026). They do not pay 85% tax. They pay normal bracket rates on 53% of the benefit.

Why extra income can cost more than the bracket suggests

In the range where more income makes more of your Social Security taxable, each extra dollar can raise your taxable income by more than a dollar. That is why some people call it a tax torpedo. A large Roth conversion or a big withdrawal in a year when you are collecting Social Security can land right in this range. The Roth conversion guide shows how to check.

Other points

• States. Most states do not tax Social Security benefits, but a few do. Check your own state.
• Roth withdrawals. Qualified withdrawals from a Roth account are not counted in provisional income. This is one reason Roth accounts are attractive in retirement.
• Age 65 and over. For 2025 through 2028, there is an extra $6,000 deduction per eligible person aged 65 or older, which phases out at higher income. It can reduce the tax on other income. See the figures we use.
• Withholding. You can ask Social Security to withhold federal tax from your check, so you are not surprised at tax time.