Medicare IRMAA Explained: How Income Raises Your Premiums

Most people on Medicare pay the same standard premium for Part B, which covers doctor visits and outpatient care. If your income is high enough, you pay more. The extra charge is called IRMAA, short for Income-Related Monthly Adjustment Amount, and it can also apply to Part D prescription drug coverage. It surprises many new retirees because it is based on income from two years ago, it works in steps rather than a smooth slope, and it can be triggered by one-time events such as selling a home or converting a retirement account.

What IRMAA is

Medicare Part B and Part D are partly funded by premiums and partly by general revenue. People with higher incomes are asked to pay a larger share of the cost. IRMAA is that surcharge. It does not change what coverage you receive. It only changes what you pay for it.

• Part B IRMAA is added to the monthly Part B premium. Most people have it deducted from their Social Security benefit.
• Part D IRMAA is an additional amount paid on top of your Part D plan's own premium, and it is paid to Medicare rather than to the plan.
• Medicare Advantage. If you have a Medicare Advantage plan that includes drug coverage, the Part D surcharge still applies, and you still pay the Part B premium.

The dollar amounts and income thresholds change over time. The Social Security Administration and Medicare.gov publish the current figures every year, so check those sources instead of relying on an old number.

How the two-year lookback works

IRMAA is generally based on the modified adjusted gross income (MAGI) reported on your federal tax return from two years before. A premium for one year therefore reflects income from a return filed during the previous year.

The practical effects:

1. Your first year on Medicare may reflect your last working years. If you earned a high salary right up to retirement, that income can determine your first premiums even after your pay has stopped.
2. Decisions today show up later. Income you create this year, from a large withdrawal, a sale or a conversion, can raise premiums two years from now.
3. Decisions you made two years ago show up now. A premium increase may not have an obvious cause in your current finances.

If the Social Security Administration does not have the return from two years ago, it can use the one from three years ago.

What counts as income

For this purpose, MAGI is your adjusted gross income plus any tax-exempt interest, such as interest from municipal bonds. Some items that can push it up:

• Wages, self-employment income and pensions
• Taxable withdrawals from traditional IRAs and 401(k)s
• Roth conversions, which are taxable income in the year of the conversion
• Realized capital gains, including from selling stocks, funds or a home beyond the exclusion
• Interest, dividends and rental income
• The taxable portion of Social Security benefits
• Tax-exempt interest, which is added back

Items that generally do not count: qualified Roth withdrawals, and unrealized gains that you have not sold. Money you give to charity directly from an IRA as a qualified charitable distribution is excluded from adjusted gross income, which can help keep MAGI lower for those who are eligible.

The brackets and the cliffs

IRMAA is not a percentage of your income. It is a set of income bands, and everyone whose MAGI falls into a band pays the same surcharge. Thresholds differ for single filers and for married couples filing jointly, and married people filing separately face different, lower thresholds.

Because the bands are steps, a small amount of extra income can cost far more than a small amount of extra premium. Going over a threshold by a single dollar moves you into the next tier for the entire year. That is why people sometimes call these "cliffs."

How it intersects with retirement planning

IRMAA is a good example of why retirement taxes involve more than the tax brackets. A few situations to think about:

• Roth conversions. A conversion adds to taxable income. Doing a large one in a single year can push MAGI over an IRMAA threshold two years later. Spreading conversions over several years is one way people try to manage this. See Roth conversions explained.
• Required minimum distributions. Once RMDs start, taxable income is forced up whether or not you need the cash. Planning earlier can smooth that out. See required minimum distributions explained.
• Selling a business or property. One-time gains show up in MAGI. If you can time a sale, consider whether the year matters.
• Withdrawal order. Which accounts you draw from affects your taxable income. See retirement withdrawal order.

These are things to understand and discuss with a tax professional, not a directive. For some people, paying a surcharge for a year is a perfectly reasonable cost of an otherwise beneficial decision.

How to appeal

If your income has dropped since the year the government is using, you may be able to ask for a new determination. The Social Security Administration recognizes certain life-changing events, which include:

• Marriage
• Divorce or annulment
• Death of a spouse
• Work stoppage or reduction
• Loss of income-producing property because of a disaster or other event outside your control
• Loss or reduction of certain pension income
• Receipt of a settlement from an employer or former employer due to closure, bankruptcy or reorganization

The process generally involves submitting a form, along with evidence of the event and your updated income estimate. The Social Security Administration publishes the form and instructions on ssa.gov. You can also ask for a new decision if you believe the agency used incorrect or outdated tax information, for instance if you later filed an amended return.

Keep copies of what you submit, and note that an appeal for one year does not automatically carry to the next.

Practical steps

1. Find your notice. If IRMAA applies, you will receive a letter explaining the amount and the tax year used.
2. Check the year. Confirm which return was used and whether it matches your records.
3. Look at upcoming income. Estimate the next two years of retirement income before big taxable events.
4. Know the thresholds. Look up the current bands on Medicare.gov or ssa.gov.
5. Consider the appeal. If your income has fallen because of a qualifying event, gather documentation.
6. Talk to a professional. A tax preparer or planner can model how a specific decision affects both income tax and Medicare premiums.

For the wider picture of enrollment and coverage choices, see Medicare explained.

IRMAA is not a penalty, and for most retirees it never applies. For those near a threshold it is worth understanding, because the two-year lag and the steps are what make it easy to trigger without noticing.