Why a Bigger Social Security COLA Could Lead to a Tax Headache

Key Points

• Social Security benefits will receive a 3.6% COLA in 2026.

• Although retirees may welcome the increase, larger payments could eventually push more benefits into taxable territory.

If a 3.6% Social Security cost-of-living adjustment, or COLA, sounds appealing, that is understandable. This year’s benefits rose by only 2.8%, and inflation quickly reduced the value of that increase as prices climbed after the Middle East conflict. Compared with that, a 3.6% boost may seem much more reassuring.

Still, there is a downside to a stronger Social Security COLA. The effect may not be immediate, but it could eventually create an unwelcome surprise.

Higher benefits can increase the odds of taxes

Many Social Security recipients do not pay federal taxes on their monthly checks. Whether taxes apply depends on provisional income, which is based on adjusted gross income, tax-exempt interest income, and 50% of a retiree’s annual Social Security benefits.

When provisional income reaches $25,000 for single filers and $32,000 for married couples filing jointly, Social Security benefits can become taxable. Those thresholds are low because Congress set them decades ago to strengthen Social Security’s finances, and they have never been adjusted for inflation.

That is where a larger COLA can become a problem. A 3.6% increase will raise benefits, but because those benefits are included in the provisional income formula, a bigger COLA can also make it more likely that federal taxes will apply to those checks — if not immediately, then later on.

Thanks to the One Big Beautiful Bill Act, many older Americans are currently eligible for a $6,000 senior deduction. Because of that, taxation of Social Security may be less of a concern now than later, when that deduction is scheduled to expire.

After that happens, more people could end up owing taxes on their Social Security income, especially if future COLAs remain generous. That makes it wise to understand how benefit taxation works and to plan ahead for it.

Be ready for the impact

Social Security benefits are funded through payroll taxes paid during a working career, so it is natural to assume those checks should be tax-free in retirement.

But Social Security also depends on tax revenue to support benefit payments, and that includes taxes on benefits themselves. Understanding the provisional income rules is important, because as COLAs grow larger, the chances of having benefits taxed may also rise.