IRMAA Medicare Surcharge Calculator
Find out if your income triggers Medicare Part B and Part D surcharges — and how much you can convert to Roth without crossing into a higher IRMAA bracket.
IRMAA applies to Medicare enrollees (age 65+). If under 65, this calculator shows what your surcharges will be.
2026 IRMAA is based on your 2024 income (2-year lookback). Find MAGI on your 2024 tax return, Form 1040 line 11.
Enter the amount you plan to convert from Traditional IRA/401(k) to Roth. This adds to MAGI and may increase your IRMAA tier.
What Is IRMAA and Why Does It Matter?
If you're on Medicare and your income is above certain thresholds, you pay more for Part B (medical insurance) and Part D (prescription drug coverage). These extra charges are called IRMAA — the Income-Related Monthly Adjustment Amount.
For 2026, IRMAA is determined by your 2024 Modified Adjusted Gross Income (MAGI). This 2-year lookback means that a large Roth conversion, capital gain, or retirement distribution in 2024 can unexpectedly increase your Medicare premiums in 2026.
How IRMAA Affects Roth Conversion Planning
Roth conversions are a powerful retirement tax strategy — but they add to your MAGI. Converting too much in a single year can push you into a higher IRMAA tier, adding hundreds or thousands of dollars in annual Medicare surcharges. The key is to find the sweet spot: convert as much as possible while staying within your current IRMAA bracket.
This calculator shows you exactly how much headroom you have before the next bracket, and what happens to your IRMAA if you proceed with a specific conversion amount.
The 6 IRMAA Tiers
IRMAA has 6 tiers. Tier 1 is the standard premium (no surcharge). Tiers 2–6 add progressively higher monthly surcharges to both Part B and Part D. For single filers, the Tier 1 threshold is $109,000; for married filing jointly, it's $218,000. The top tier (Tier 6) applies to individuals with MAGI over $500,000 or couples over $750,000.