06/22/2026
How Long an Increased Medicare Premium Lasts
If your Medicare Part B or Part D premium increases due to the Income‑Related Monthly Adjustment Amount (IRMAA), the higher amount generally lasts for the entire premium year — that is, from January 1 to December 31 of that year — and is recalculated annually factually.co.
How IRMAA is Determined
Two‑year lookback rule: Medicare uses your modified adjusted gross income (MAGI) from two years earlier to set your IRMAA tier for the current year factually.co.
For example, your 2023 tax return is used to determine your 2025 Part B/Part D premium Medical News Today.
If your income is above the threshold for a higher bracket, you pay the corresponding IRMAA on top of the standard premium for the whole year.
When the Increase Ends
Annual recalculation: Every January, Medicare recalculates premiums for the upcoming year based on the prior‑year tax data factually.co+1.
If your income drops in a later year (e.g., due to a qualifying life‑changing event or corrected tax data), you can request a new determination and may drop into a lower IRMAA bracket factually.co.
Until then, the higher premium remains in effect for the rest of the current premium year.
Key Points
The increase is not a one‑time fee — it’s a monthly surcharge added to your Part B or Part D premium for the year factually.co.
The standard Part B premium also increases annually, regardless of IRMAA, so even if you’re in the lowest bracket, your base premium still rises each year InsuredAndMore.com+1.
You can appeal an IRMAA determination if you believe your income should be lower, but this is usually only done if there’s a significant change in circumstances factually.co.
In short: An increased Medicare premium from IRMAA lasts for the full year it’s calculated, and the next year’s amount will be based on your income from two years earlier.