Roth Conversion IRMAA Tipping Point 2027 Calculator
Medicare IRMAA surcharges jump in cliff-style brackets — one extra dollar of MAGI can cost $1,000+ in annual Part B and Part D premiums. This calculator finds the exact Roth conversion amount that keeps you in the current IRMAA bracket and the max conversion size before triggering the next surcharge tier.
What Is the IRMAA Tipping Point?
The Income-Related Monthly Adjustment Amount (IRMAA) is a Medicare premium surcharge that applies above income thresholds. Brackets are cliffs — not phased — so crossing a tier boundary by $1 triggers the full surcharge for 12 months. For 2027 (based on 2025 MAGI thanks to the 2-year lookback), the single-filer Part B base premium plus surcharges range from about $185/month (standard) to over $600/month (top tier). For Married Filing Jointly, each spouse pays their own IRMAA — so a small conversion can cost both spouses doubled surcharges. Source: SSA POMS HI 01101.020 and CMS 2027 Medicare premium projections. Last updated: May 2026.
Estimated 2027 IRMAA Brackets (Based on 2025 MAGI)
| Single MAGI | MFJ MAGI | Part B Surcharge/mo (per person) | Part D Surcharge/mo |
|---|---|---|---|
| ≤ $106,000 | ≤ $212,000 | $0 | $0 |
| $106K–$133K | $212K–$266K | ~$74 | ~$13 |
| $133K–$167K | $266K–$334K | ~$185 | ~$34 |
| $167K–$200K | $334K–$400K | ~$297 | ~$55 |
| $200K–$500K | $400K–$750K | ~$408 | ~$76 |
| ≥ $500K | ≥ $750K | ~$444 | ~$85 |
The 2-Year Lookback Rule (Why 2025 MAGI Matters in 2027)
IRMAA is set by the Social Security Administration using your tax return from 2 years prior. So your 2027 Medicare premiums are determined by your 2025 MAGI (reported on your 2025 return filed in 2026). This means Roth conversions done in 2025 — when most pre-Medicare retirees feel safe converting — bite back in 2027 as IRMAA surcharges. Always run conversion math against the 2-year-future Medicare bracket schedule, not just current year. You can request a reduction via Form SSA-44 if you experience a life-changing event (retirement, loss of pension, divorce), but conversions don't qualify.
Tipping Point Strategy: Fill to the Edge
The optimal Roth conversion sizes UP TO (but not over) the next IRMAA cliff. A $1,000 conversion that crosses the line can cost $2,000+ in extra Medicare premiums for both spouses combined. A $50,000 conversion that stays inside the current tier costs only federal income tax. Use this calculator each tax-year to find your headroom, then size conversions to fill exactly to within $500–$1,000 of the threshold (safety buffer for year-end portfolio gains).