Question 1

How does the IRMAA two-year lookback work?

Accepted Answer

Each fall, Social Security pulls your Modified Adjusted Gross Income (MAGI) from the IRS for the tax return TWO years prior to the upcoming Medicare premium year. For 2026 Part B and Part D premiums, that is your 2024 return filed in April 2025. The lookback is a hard cliff: one dollar over an IRMAA threshold pushes the entire year's surcharge up to the next tier. A Roth conversion at age 63 or 64 can therefore land on your Medicare premium two years later, even though your current retirement income is well below the threshold.

Question 2

What are the 2026 IRMAA brackets?

Accepted Answer

Six tiers, based on MAGI from the tax return two years prior. Tier 0 (no surcharge): up to $109,000 single / $218,000 MFJ. Tier 1: $109,001-$137,000 single / $218,001-$274,000 MFJ, surcharge $81.20 Part B + $14.50 Part D = $95.70/mo per person. Tier 2: $137,001-$171,000 single / $274,001-$342,000 MFJ, $240.40/mo. Tier 3: $171,001-$205,000 single / $342,001-$410,000 MFJ, $385.00/mo. Tier 4: $205,001-$500,000 single / $410,001-$750,000 MFJ, $529.60/mo. Tier 5 (top): over $500,000 single / over $750,000 MFJ, $578.00/mo.

Question 3

What is Form SSA-44 and when can I file it?

Accepted Answer

SSA-44 is the Medicare Income-Related Monthly Adjustment Amount Life-Changing Event form. You file it with Social Security to request that they use a more recent year's MAGI for the IRMAA calculation instead of the two-year-old return. Qualifying life events include retirement or work stoppage, work reduction, loss of pension income, marriage, divorce, death of a spouse, and certain employer settlements. Submit the form to your local Social Security office; supporting documentation (last pay stub, retirement letter, etc.) is required.

Question 4

Are IRMAA brackets the same for married couples?

Accepted Answer

MFJ thresholds are roughly 2x the single-filer thresholds, except for the top tier. For tiers 0-3 the MFJ cap is exactly 2x the single cap. For the top finite tier (tier 4), CMS sets the MFJ cap at $750,000 — only 1.5x the single $500,000 cap. The surcharge dollars are the same per Medicare-enrolled person regardless of filing status, so a couple where both spouses are on Medicare pays 2x the per-person amount.

Question 5

Which Roth conversion years are 'free' of IRMAA risk?

Accepted Answer

Conversions at age 62 or earlier do not enter the IRMAA lookback at all, because the lookback year is before the first IRMAA-relevant Medicare year. This is the cleanest window for large Roth conversions if you have already retired. At ages 63 and 64, anything reported on those returns hits the 65/66 Medicare bills; size conversions to stay just below the next IRMAA threshold rather than the top of the federal 22% bracket. At 65 and beyond, you are inside the lookback for life, and every conversion year shows up on the Medicare premium two years later.

Tier	MAGI (single)	MAGI (MFJ)	Part B surcharge	Part D surcharge	Total/mo
0 (base)	$0 – $109,000	$0 – $218,000	$0.00	$0.00	$0.00
1	$109,001 – $137,000	$218,001 – $274,000	$81.20	$14.50	$95.70
2	$137,001 – $171,000	$274,001 – $342,000	$202.90	$37.50	$240.40
3	$171,001 – $205,000	$342,001 – $410,000	$324.60	$60.40	$385.00
4	$205,001 – $500,000	$410,001 – $750,000	$446.30	$83.30	$529.60
5 (top)	Over $500,000	Over $750,000	$487.00	$91.00	$578.00

IRMAA Two-Year Lookback Projector (2026)

Your filing status & Medicare timeline

Projected MAGI by year

🔒 PRO: 5- and 10-year projections

Surcharge projection

2026 IRMAA brackets (CMS)

How the 2-year lookback works

Related calculators & guides

Primary sources cited