Short answer: For 2026 premiums, Medicare generally reviews 2024 Medicare MAGI. A large income event today can appear in your Medicare costs later.
Why age 63 matters
If Medicare starts at age 65, the tax year when you are age 63 may be the first year used for your first Medicare IRMAA decision. That does not mean every person must avoid income at age 63. It means Roth conversions, RMD planning, capital gains, and home sales deserve a quick IRMAA check before the year closes.
What income gets reviewed?
IRMAA uses Medicare MAGI. For most planning conversations, that means adjusted gross income plus tax-exempt interest. Taxable IRA withdrawals, Roth conversions, capital gains, pensions, and taxable Social Security can all matter.
Review what counts in Medicare MAGI
Education sponsor placement for annual IRMAA threshold updates or retirement income planning resources.
Simple lookback checklist
- Estimate this year's Medicare MAGI before making a large income move.
- Compare the estimate with the IRMAA brackets for the Medicare premium year you are planning around.
- Remember that a one-year spike usually affects only one premium year unless income remains high.
- Do not assume SSA-44 applies just because the income was unusual.
Official source notes
Medicare.gov states that the Part B premium can be higher depending on income. Social Security handles requests to lower IRMAA when a qualifying life-changing event reduces household income.
Next step: run a surcharge estimate and save the IRMAA planning checklist.