MEDICARE PART B PREMIUMS EXPLAINED

Medicare typically determines your Part B premium based on your income from two years prior. For example, in 2025, they review your 2023 tax return. Specifically, they use your Modified Adjusted Gross Income (MAGI), which is calculated by adding line 11 and line 2a of your IRS Form 1040.

Start by identifying how you file your taxes— individual, joint, or married filing separately —to find the correct column to review. Then, reference your 1040 tax return for the year Medicare is reviewing. This will help you determine the Part B premium you’ll be responsible for. These premiums are per person so couples that file join tax returns will each pay the same Part B premium from one of the amounts listed below.