If your income crosses certain thresholds, Medicare adds a surcharge to your Part B and Part D premiums. Enter your income to see your tier, what you'd pay, and how much headroom you have before the next cliff.
IRMAA, the Income-Related Monthly Adjustment Amount, is a surcharge Medicare adds to your Part B and Part D premiums once your income passes certain thresholds. Higher earners pay more for the same coverage. The surcharge is set in tiers, and it applies per person, so a married couple on Medicare can each owe it.
Medicare doesn't use your current income. It uses your modified adjusted gross income from two years earlier, the most recent return available when premiums are set. This lookback is what makes IRMAA sneaky: a large Roth conversion or a big capital gain at 63 can raise your Medicare premiums at 65, long after you've forgotten the transaction. Planning conversions with this lag in mind is a core retirement-tax skill.
IRMAA tiers are hard edges. Earn one dollar over a threshold and you pay the full higher surcharge for the entire year. There's no gradual phase-in. That makes the headroom to the next tier genuinely valuable: keeping income just below a line can save hundreds or thousands. People manage this by timing conversions, spreading gains across years, or using qualified charitable distributions, often with a tax professional.