How Medicare Part B Premiums Work and What IRMAA Means for Your Costs

What Part B Premiums and IRMAA Are

Medicare Part B covers doctor visits, outpatient care, and medical equipment. Most people pay a monthly premium for it — the amount you pay depends on your income from two years ago, not what you earn right now. IRMAA stands for Income-Related Monthly Adjustment Amount, and it's an extra charge added to your Part B premium if your income exceeds a certain threshold.

The key thing to understand: your Part B cost is not the same for everyone. Two people turning 65 in the same month can pay very different premiums based on their 2022 tax return (if they're enrolling in 2024). This matters because the income limits change yearly, and the extra charges can be substantial.

Key Takeaways

• Part B premiums are based on your income from two years prior, reported on your federal tax return or IRS Form SSA-44 if you didn't file taxes.
• IRMAA adds extra charges to your premium if your income exceeds the yearly threshold, which varies by filing status and changes annually.
• You can request a review if your income dropped due to retirement, job loss, or divorce — Social Security will recalculate your premium based on your current year's income.
• The standard Part B premium covers about 25 percent of the program's costs; the rest comes from general tax revenue.
• Your premium amount is deducted from your Social Security check, or you pay Medicare directly if you don't receive Social Security.

How Your Income Affects Your Part B Premium

Medicare uses your Modified Adjusted Gross Income (MAGI) from your tax return filed two years before you enroll. If you're turning 65 in 2024, Medicare looks at your 2022 tax return. This two-year lag means your premium doesn't change immediately when your income changes — it changes when that older tax year finally affects your billing.

The income thresholds are different depending on whether you file taxes as single, married filing jointly, married filing separately, or head of household. A single person with $97,000 in MAGI pays a different IRMAA charge than a married couple with the same combined income. Medicare sends you a notice each year showing what income they used and what your premium will be.

If you didn't file a tax return, you can submit IRS Form SSA-44 to Social Security to report your income. This matters if you're self-employed, have very low income, or live abroad — Social Security needs some record of your income to set your premium correctly.

What IRMAA Charges Actually Cost

IRMAA is tiered. The higher your income, the more you pay. There is no single IRMAA amount — it depends on which income bracket you fall into. In 2024, for example, a single person with MAGI between $97,000 and $123,000 pays one amount, while someone with MAGI between $123,000 and $152,000 pays more. The brackets and dollar amounts change every year.

The extra charge is added directly to your Part B premium. So if the standard premium is $164.90 per month and your IRMAA charge is $65.90, you pay $230.80 total. This amount comes out of your Social Security check if you receive benefits, or you pay Medicare directly if you don't.

IRMAA also affects Part D (prescription drug coverage) and Part C (Medicare Advantage) premiums. If you have IRMAA for Part B, you likely have it for Part D as well. Part C plans sometimes charge IRMAA separately; it depends on the plan.

When You Can Request a Premium Recalculation

If your income dropped significantly since the tax year Medicare is using, you can ask Social Security to recalculate your premium based on your current year's income. This is called a Life-Changing Event request. Common reasons include retirement, job loss, death of a spouse, divorce, or a substantial decrease in income or benefits.

You must request this within 60 days of the event. Social Security will ask for proof — a termination letter from your employer, a divorce decree, a death certificate, or a recent tax return showing lower income. If approved, your new premium takes effect the month after Social Security processes your request.

This recalculation uses your current year's income, not a future tax year. So if you retired in June 2024, you can report your 2024 income (which will be lower than 2022) to reduce your premium starting in July or August. You don't have to wait until 2026 when the 2024 tax year finally affects your billing.

How to Find Out What You'll Pay

Medicare sends you a notice called the Initial Enrollment Notice before you turn 65. This notice shows the standard Part B premium for the year you're enrolling. If you have IRMAA, you'll receive a separate notice called the Notice of Medicare Premium Amount that breaks down the standard premium and the IRMAA charge.

You can also call Social Security at 1-800-772-1213 to ask what your Part B premium will be. Have your most recent tax return handy. Social Security can tell you the income they have on file and what that means for your premium. If the income is wrong, you can correct it on the spot.

Medicare.gov has a tool that shows current-year premium amounts and IRMAA brackets, though it does not calculate your personal premium. The tool is useful for understanding the structure and seeing how much premiums have changed year to year.

What Happens If Your Income Changes After You Enroll

Your premium is locked in for the calendar year based on the tax year Medicare is using. If your income changes in January, it won't affect your 2024 premium — it will affect your 2025 premium (based on your 2023 tax return). The only exception is if you experience a may have access to life-changing event and request a recalculation within 60 days.

If you think Social Security has the wrong income on file, ask them to review it. Sometimes tax returns are mismatched, or income is reported under a slightly different name. Getting the record corrected now prevents overpaying for months.

When you turn 66, 67, or any age after initial enrollment, your premium recalculates automatically based on the most recent tax year in the system. You don't have to do anything — Medicare handles it. You'll receive a new notice showing the updated amount.

Part B Premium Costs and What They Cover

The standard Part B premium covers doctor office visits, lab work, imaging (X-rays, ultrasounds), outpatient surgery, and durable medical equipment like wheelchairs and oxygen. It does not cover hospital stays (that's Part A), prescription drugs (that's Part D), or routine dental, vision, or hearing care.

You also pay a yearly deductible before Part B coverage kicks in, and then you typically pay 20 percent of the cost of covered services. The premium is just the monthly fee — it's separate from what you pay when you actually use care.

If you delay enrolling in Part B and don't have other may have access to coverage, you may owe a permanent penalty on top of your premium for each month you were late. This penalty is 10 percent of the standard premium for each 12-month period you didn't enroll. It's added to your premium for life, so enrolling on time matters.

Frequently Asked Questions

Can I reduce my IRMAA by giving money away or moving it to savings?

No. Medicare uses your Modified Adjusted Gross Income from your tax return, which is calculated before charitable donations or savings moves. Rearranging money after the tax year won't change what Medicare sees. The only way to lower IRMAA is to have lower actual income in the tax year Medicare is using, or to request a recalculation if you've had a may have access to life-changing event.

What if I'm still working and have high income now, but I'll retire next year?

Your premium will be based on your current high income for the next two years. When you retire, you can request a recalculation within 60 days, and your premium will drop based on your retirement income. Until then, you'll pay IRMAA. This is one reason some people delay Medicare enrollment if they're still working and have employer coverage.

Do I have to take Part B, or can I skip it?

If you're receiving Social Security, Part B is automatic at 65 unless you actively decline it. If you're not receiving Social Security, you must enroll during your Initial Enrollment Period (the seven months around your 65th birthday) or pay a permanent penalty. The exception is if you have may have access to employer coverage — then you can delay without penalty.

Who pays the other 75 percent of Part B costs if the premium only covers 25 percent?

General federal tax revenue covers the remaining 75 percent. This is why Part B is sometimes called a "subsidized" benefit — the government funds most of it regardless of your income. IRMAA is designed to ask higher-income beneficiaries to pay a larger share of their own costs, but even with IRMAA, the government still covers a substantial portion.

Can I appeal if I think my IRMAA is wrong?

Yes. If you believe Social Security has incorrect income information, you can request a reconsideration. You'll need to provide documentation — a corrected tax return, a letter from your employer, or other proof. If you had a life-changing event that Social Security didn't know about, you can also appeal within 60 days of the event. Contact Social Security or Medicare to start the appeal process.