What a zero COLA means for your Medicare premium

social security check
While no one will get a raise from Social Security next year, 16.5 million people will have to pay a lot more for Medicare.

Although no one will get a raise from Social Security this year, most retirees won't see a hike in their Medicare premiums either.

The bad news is that leaves 16.5 million people to shoulder the increase for Medicare Part B. Those Americans will see a 52% jump.

Here's how it works: If your Medicare Part B payment is deducted straight out of your Social Security check, it's likely that the amount will be the same as last year: $105 a month. That's because roughly 70% of Medicare recipients are protected by law from increases when the cost of living adjustment (COLA) in Social Security amounts to zero.

The law is in place to make sure people don't see a net decrease in their Social Security checks year after year, said Anqi Chen, a researcher at the Center for Retirement Research at Boston College.

But that means the remaining 30% of Medicare enrollees, many of whom are not on Social Security and therefore aren't protected by the law, have to shoulder the increased cost of the program. Their Medicare Part B premiums are expected to jump 52% to $160 a month, according to the Medicare Trustees Report.

Related: No raise for 65 million on Social Security

This hike will impact four groups of people.
- Retired federal workers who get a pension from the government instead of Social Security.
- Those with income above $85,000 a year, who already pay more for Medicare Part B than everyone else.
- People who are signing up for Medicare for the first time.
- Those whose premiums are paid for by Medicaid.

With the exception of high income earners, those people seeing a spike in their Medicare premium don't get Social Security at all or didn't have any deductions for Medicare Part B last year.

Keep in mind, Medicare Part B (which covers doctors' services and outpatient care) is only part of your health care costs. There's Medicare Part A, which covers hospital insurance. But most people don't pay a premium for that.

You do pay premiums for any prescription drug coverage you might have, which you can get one of two ways. There's the Medicare Advantage Plan, where premiums are expected to stay about the same for a majority of enrollees in 2016. It costs about $33 a month on average, according to the Centers for Medicare and Medicaid Services.

You could instead get a supplemental prescription drug plan. Those premiums are expected to increase by an average of 13% to $41, according to the Kaiser Family Foundation. That's the biggest increase since 2009.

Related: Here's one fix for high drug prices

Groups like the AARP are urging Congress to protect any senior from having to pay the 52% jump in Medicare Part B premiums.

But someone has to fund the program. The Center for a Responsible Federal Budget is asking that any effort to prevent the huge spike does not add to the deficit or contribute to the rising cost of Medicare.

There were substantial spikes in Medicare Part B premiums for some seniors the last time Social Security benefits were kept flat, too. Their payments increased by 17% to $110.50 in 2010 and jumped to $115.40 a year later, according to the Center for Retirement Research.