Taxes take a bite of more people's Social Security benefit each year. Here's why.

If you feel like your Social Security benefits aren’t going very far despite big cost-of-living increases the past few years, there’s a reason for it, and inflation’s only part of the explanation.

The government regularly adjusts many things for inflation: federal tax brackets; contribution limits for retirement accounts; the size of the standard deduction on taxes; Social Security’s cost-of-living adjustment, or COLA, among others.

But one thing that has never been adjusted for inflation is the federal income threshold to determine if you’ll have to pay taxes on your Social Security benefit. That means with each passing year, an increasing proportion of seniors have been reaching those low thresholds and having to pay taxes on their benefits.

“This is a stealth tax,” said Jordan Gilberti, senior lead planner and certified financial planner at financial advisory firm Facet. "Everyone knows Social Security gets taxed, but rarely do they see how it’s taxed. People’s jaws would fall to the ground.”

How is Social Security taxed and what are the tax thresholds?

Depending on your so-called provisional income, up to 85% of your Social Security benefits can be taxed. Provisional income includes your gross income, tax-free interest you received, like from a municipal bond, and 50% of your Social Security benefits.

If you’re single and this total is less than $25,000, or if you're filing jointly and it's less than $32,000, none of your Social Security is federally taxed.

If it’s between $25,000 and $34,000 for single filers or $32,000 and $44,00 for joint filers, up to half your Social Security is taxed. These thresholds have remained the same since taxes on Social Security benefits were introduced in 1984.

And up to 85% is taxed for anything above $34,000 for single filers and $44,000 for joint filers. These thresholds were added in 1993.

For example, if you have $50,000 in income and get $1,500 a month from Social Security, you'll pay taxes on 85% of your $18,000 in annual benefits, or $15,300.

You can file quarterly estimated tax returns with the IRS or ask Social Security to withhold federal taxes from your benefit payment.

What’s wrong with these Social Security tax thresholds?

With such low-income thresholds, a larger proportion of beneficiaries owe taxes on Social Security every year. In 1984, the average monthly check for an individual was $314 and $472 for joint filers. In 2023, it’s $914 and $1,371, respectively.

The percentage of all tax returns with taxable Social Security benefits grew to 33% in 2017 from 7.4% in 1999, and the Congressional Budget Office predicts that it will grow to more than 50% by 2046. And, since 1984, the proportion of beneficiary families whose benefits are taxed has risen over time from less than 1 in 10 to more than half, the Social Security Administration says.