Medicare IRMAA Surcharge

Healthcare Finance

Updated Apr 2026 • Has calculator

Additional Medicare Part B premium paid by higher-income enrollees based on MAGI.

What is Medicare IRMAA?

The Income-Related Monthly Adjustment Amount (IRMAA) is an additional surcharge added to the standard Medicare Part B premium for beneficiaries whose Modified Adjusted Gross Income (MAGI) exceeds certain thresholds. The SSA uses MAGI from two years prior (i.e., 2026 premiums are based on 2024 income). For 2025, the standard Part B premium is $185.00/month; higher earners pay up to $628.90/month depending on income tier and filing status. IRMAA also applies to Part D prescription drug coverage.

Formula

Part B Premium = Standard Premium + IRMAA Surcharge (based on income tier)

Worked Example

2025

Step 1 Single filer, 2023 MAGI: $140,000

Step 2 Income falls in $133,000–$167,000 bracket

Step 3 2025 Part B premium: $370.00/month

Step 4 → $185/mo extra vs. the standard $185/mo base premium

Source: CMS Medicare Costs 2025 (2025-01-01)

Calculate Medicare IRMAA

Modified AGI (2 years prior)

SSA uses MAGI from 2 tax years ago

Filing Status

single or joint

Monthly Part B Premium

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Not investment advice.

How to Interpret Medicare IRMAA

< 200

Base Tier — standard premium, no surcharge

200 – 400

Tier 1–2 — moderate income surcharge applies

400 – 600

Tier 3–4 — significant surcharge, consider tax planning

> 600

Top Tier — maximum surcharge; Roth conversions may help

📚 Retirement Planning — Complete the path

Sources