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Ask the Expert Retirement illustration
Robert A. Di Ieso, Jr.

Q: I got my annual notice from Social Security this week for 2015 and was surprised to find out that the Medicare premiums for me and my wife were going up for this year because of the amount of money I made in 2013. I did not know Medicare premiums were adjusted based on income. I am 71. Is there anything I can do? – Norman Medlen

A: You won't be able to change your premiums for this year, but there are moves that can help lower your future costs.

First, though, realize that your confusion is understandable. Many people don’t know that Medicare premiums are calculated based on income, says Nicole Duritz, vice president of Health and Family Education and Outreach for AARP. Some people even believe that Medicare, which most Americans are eligible to receive when they turn 65, is completely free. It’s true that most people don’t pay for Medicare Part A, which covers hospitalization, but that’s because they have contributed to Medicare throughout their careers through payroll taxes.

But your income determines how much you pay for Medicare Part B, which covers routine medical care, including doctor visits and outpatient services, such as physical therapy and X-rays. Under the rules, your income can include a salary from working, as well as proceeds from the sale of a house or withdrawals from a portfolio.

Granted, the income thresholds are relatively high. If an individual earns $85,000 or less, or a married couple earns $170,000 or less, the premium is $104.90 a month. People earning more than $85,000, or a couple earning more than $170,000, will pay $146.90 to $335.70 a month depending on their income. Only an estimated 5% of Medicare recipients pay more than the basic $104.90 level. The premiums are deducted from your Social Security check.

Premiums for Medicare Part D, which is for prescription drug coverage, are also income-based, which add anywhere from $12.30 to $70.80 a month to the premiums charged by the plan you select.

Still, there's good news: your premiums are re-evaluated each year based on your most recent tax return. So if the money you received was a one-time windfall, your premiums will drop back down the following year.

To make sure your premiums stay affordable, do some advance planning, says Rich Paul, president of investment advisory firm Richard W. Paul and Associates. That's especially true if you think you may have more windfalls ahead. “It’s not just your Medicare premiums that will go up—the additional income may bump you into a higher tax bracket and your income taxes will go up too,” says Paul.

For example, if you are converting a traditional IRA to a Roth, consider spreading the amounts over several years. That way, you won't have a large one-time jump in your income. Or make a large charitable contribution at the same time as you convert, since the deduction will offset some of your tax bill.

In addition to the premiums, the size of Medicare's out-of-pocket costs surprises many people, says Duritz. Medicare Part B covers roughly about 80% of your medical bills, but you have to pay the other 20%, including deductibles, co-insurance and co-pays. And unlike many employer plans, Medicare doesn’t cover some major medical expenses, including glasses and dental work.

To cover those gaps, many people opt for a Medicare supplemental plan or Medicare Advantage. How much you pay depends on where you live and the status of your health, in addition to your income. “If you’re healthy, you won’t incur the same costs as someone with a chronic condition because you don’t need as much care or medication,” says Duritz.

Fortunately, there are a number of ways you can lower costs. She suggests getting regular health screenings to catch any problems early, exercising and maintaining healthy weight. If you are on medications, talk to your doctor about lower-cost options. “It doesn't have to be a generic—it could just be an older brand name,” says Duritz. “We have had people cut their prescription drug costs by $1,000 or more using alternative medications.”

It's also important to reevaluate your Medicare plans during annual open enrollment, which runs from October 15th to December 7th. Plans and costs change every year—and your medical needs may change too.

For help finding the best options, try AARP’s “doughnut hole” calculator—named for the gap in prescription drug coverage under Medicare Part D—to find suggested drug alternatives to discuss with your doctor. AARP’s Medicare Health Care Cost calculator will estimate your overall Medicare costs and suggest ways to minimize your spending. And AARP’s Question and Answer tool walks you through all the costs of Medicare and how it works. With this information, you'll have a better idea of the costs to expect from Medicare.

More on Medicare from Money's Ultimate Retirement Guide:

What is Medicare?

What is Medigap insurance?

How do I select a Medigap policy?

Read next: So You’re Retired! Now What?

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