1. Medicare Premium Components

The Medicare Part B premium consists of a standard base amount plus an Income-Related Monthly Adjustment Amount (IRMAA) for higher-income beneficiaries. The calculation is based on your Modified Adjusted Gross Income (MAGI) from two years prior.

2. How Premium is Calculated

The premium calculation follows this formula:

Where:

• Base Premium — Standard amount all beneficiaries pay (for 2025: $174.70)
• IRMAA — Income-related surcharge based on MAGI brackets
• MAGI — Modified Adjusted Gross Income from IRS tax return

3. Understanding IRMAA

Details: IRMAA is calculated based on income brackets that differ for single filers and married couples filing jointly. The income thresholds are adjusted annually.

4. Using the Calculator

Tips: Enter your MAGI from two years prior (e.g., 2023 income for 2025 premiums) and select your filing status. The calculator will show your total premium, base amount, and any IRMAA surcharge.

5. Frequently Asked Questions (FAQ)

Q1: Why is Medicare using income from two years ago?
A: Medicare uses the most recent tax data available from the IRS, which typically lags by two years.

Q2: Can I appeal my IRMAA determination?
A: Yes, if you've had a life-changing event that reduced your income (retirement, divorce, etc.), you can file an appeal.

Q3: Does IRMAA affect Medicare Part D?
A: Yes, higher-income beneficiaries also pay an IRMAA surcharge for Part D prescription drug coverage.

Q4: How often are IRMAA brackets adjusted?
A: Brackets are adjusted annually for inflation by the Centers for Medicare & Medicaid Services.

Q5: Where can I find official IRMAA brackets?
A: The official brackets are published annually in the Federal Register and on Medicare.gov.