An income-related monthly adjustment amount, or IRMAA, is an additional amount for Part B and Medicare drug coverage. It is not a different insurance plan or a late-enrollment penalty. Social Security makes the determination using tax information.
Which income is used?
For this purpose, modified adjusted gross income generally means adjusted gross income plus tax-exempt interest. Social Security normally uses tax data from two years earlier. For 2026, that usually means the 2024 tax return filed in 2025. Filing status affects the applicable brackets.
The result may not resemble your current monthly income after retirement. Read the notice for the tax year, filing status and income used before assuming the calculation describes what you earn now.
Separate the charges
Part B IRMAA increases your Part B payment. Part D IRMAA is paid separately from the drug plan’s own premium, generally through benefit withholding or a federal bill. Choosing a lower-premium drug plan does not by itself eliminate the income adjustment.
When income falls
A qualifying life-changing event, such as retirement, reduced work, marriage, divorce or a spouse’s death, can support a request for a new determination when income falls. Form SSA-44 is one way to present the event and more recent income. A reduction is not automatic, and ordinary investment fluctuations are not necessarily qualifying events.
If the tax information is wrong or amended, a correction may be appropriate. If you disagree with the decision, review the reconsideration instructions and deadline in the notice. A life-event request and an appeal are different processes.
Prepare before contacting Social Security
- Keep the premium notice and note its date.
- Identify the tax year and filing status used.
- Gather documentation of the event, such as a retirement letter.
- Prepare a supportable current-year income estimate and relevant tax records.
- Ask your tax professional about uncertain income items.
- Keep a copy of what you submit and the resulting decision.
A retirement example
A person retires in 2026, but the initial premium determination reflects employment income from 2024. The next step is not to switch drug plans solely to escape the adjustment. It is to document the retirement and changed income for Social Security to evaluate.
Common question: Can Coverage Relay waive IRMAA? No. Our agents can help you understand how it fits into a coverage budget, but Social Security determines the adjustment. Tax decisions belong with your tax adviser, and the official notice controls payment obligations.
Sources and update notes
Published by My Coverage Relay. Updated September 24, 2026. This guide explains general rules; individual eligibility, plan terms and state protections require a specific review.