Seniors awaiting an increase in their Social Security checks next year may be upset to discover that a chunk of that extra money is already spoken for.

The Centers for Medicare and Medicaid Services (CMS) announced that 2025 monthly Part B premiums will climb to $185, an increase of $10.30 from $174.70 in 2024. And the annual Part B deductible, which most people must pay before their Medicare coverage begins, will rise by $17, or 7%, to $257 from $240.

That news follows the Social Security Administration’s announcement of a 2.5% cost-of-living adjustment (COLA) for 2025, which will add about $50 to the average monthly benefit of roughly $1,900, according to the SSA.

Ideally, that bump in benefits would provide some breathing room to the more than 72 million retired senior citizens and disabled workers who have grappled with higher prices in recent years.

Next year, maybe not.

“This marks the second year in a row where the Part B premium has risen by nearly 6%,” Mark Miller, a retirement expert and author of "Retirement Reboot," told Yahoo Finance.

“The high dollar amount of the increase will squeeze the Social Security COLA for seniors,” he said. “The squeeze will be most painful for people with lower benefit amounts.”

For example, Miller said, someone with a $1,200 monthly benefit will see their COLA reduced to 1.6% once the Medicare increases are factored in. But for someone with a high benefit of $3,500, their COLA still increases by 2.2 percent.

In addition, the Medicare Part A deductible that beneficiaries pay if admitted to the hospital will be $1,676 in 2025, an increase of $44 from $1,632 in 2024. Coinsurance amounts for hospital and skilled nursing care will also rise by 2.7 percent.

Not everyone will feel the pinch. Under Social Security “hold harmless” rules, a person’s Part B premium increase cannot be larger than their COLA. People receiving less than about $415 in monthly Social Security benefits will not be charged the full Part B premium increase, per Phil Moeller, a Medicare and Social Security expert author of the book, “Get What’s Yours for Medicare.”

In general, people who receive Social Security benefits are notified by mail in early December about their new benefit amount. Most beneficiaries can also view their COLA notice online through their personal Social Security account at ssa.gov/myaccount/.

Read more: How to find out your 2025 Social Security COLA increase

The more you earn, the more you pay

Since 2007, a beneficiary’s Part B monthly premium is based on his or her income. About 8% of Medicare users earn too much to qualify for the standard Part B and Part D premiums and must pay the surcharges, known as Income-Related Monthly Adjustment Amounts (IRMAA). Details can be found on the CMS fact sheet.