What IRMAA is
IRMAA stands for income-related monthly adjustment amount. It is an extra charge added to your Medicare Part B (medical) and Part D (prescription drug) premiums if your income is above certain lines. Most people pay the standard Part B premium, which is $202.90 a month in 2026. Higher-income households pay that plus a surcharge.
The 2026 income lines
| Step | Single filer (income over) | Married filing jointly (income over) | Extra Part B per person, per month |
|---|---|---|---|
| Standard | up to $109,000 | up to $218,000 | $0 |
| Step 1 | $109,000 | $218,000 | $81.20 |
| Step 2 | $137,000 | $274,000 | $202.90 |
| Step 3 | $171,000 | $342,000 | $324.60 |
| Step 4 | $205,000 | $410,000 | higher steps apply above this line |
There is an additional surcharge on Part D at each step too. The amounts change each year. See Medicare.gov for the current table, including the highest steps.
The two-year look-back
Medicare looks at your tax return from two years earlier. Premiums in 2026 are based on your 2024 income, and income you have in 2026 sets your premiums in 2028. A one-time spike in income, like a large Roth conversion, selling a rental property, or a big retirement withdrawal, can raise your Medicare premiums two years later.
The income used is your modified adjusted gross income (MAGI): your adjusted gross income plus tax-exempt interest.
It is a cliff, not a slope
Going over a line by a single dollar moves you to the next step for the whole year. At step 1 with one person on Medicare, that is $81.20 × 12 = about $974 a year more. At step 2 it is $202.90 × 12 = about $2,435 a year. For a couple where both are on Medicare, double it.
Example from Case File No. 3
Linda converts all $260,000 of her 401(k) in one year. Her income that year is $340,000, which is over the $274,000 line, so step 2. With one person on Medicare in two years, that is about $2,435 a year in extra Part B premium, plus drug coverage surcharges. A smaller slice, spread over several years, can stay under the line.
Ways to stay under a line
- Spread a conversion over several years rather than one big year.
- Time large one-time income. If you can choose which year to sell a rental or realize a large gain, remember the look-back.
- Qualified charitable distributions. Giving from an IRA after 70½ can reduce income that counts for IRMAA.
- Know the line before you act. A tool like Roth Check shows which line you would cross.
You can appeal in some cases
If your income dropped because of a life-changing event, such as retiring, reducing your work hours, the death of a spouse, a marriage or divorce, or the loss of income-producing property or a pension, you can ask Social Security to use a more recent year. The request is made on Form SSA-44. SSA decides each case. Appeals do not apply just because you chose to convert a retirement account.
Where to check
Medicare sends a notice if IRMAA applies to you. Review it, and check the lines for the current year at Medicare.gov. If your numbers are close to a line, check with a tax professional before you make a big move.
Try it with your own numbers
The free Roth Check runs this check on your figures. Nothing you type leaves your device.
Watch the case
This guide goes with Case File No. 3: Roth conversion: all at once?. See the video and the verdict →
Sources
- Medicare.gov: What does Medicare cost?
- SSA: Medicare premiums, rules for higher-income beneficiaries
- SSA: Form SSA-44, request to reduce income-related premium
General information, not financial, tax or legal advice. Rules change and every household is different. See how we check our numbers.