# US Medicare premium calculation and IRMAA surcharges

> Live situation record from CLSTR: https://clstr.news/situations/us-medicare-premium-calculation-and-irmaa-surcharges
> Updated: 2026-08-07T15:25:00.000Z. Sources: 2. Developments: 2.

The structure of US Medicare Part B premiums is determined by the Centers for Medicare and Medicaid Services (CMS) based on anticipated program costs rather than Social Security benefit amounts. For 2026, the standard premium is set at $202.90, with the goal of offsetting approximately 25% of total program costs.

To manage costs for different income levels, the program utilizes specific provisions. The "hold harmless provision" protects lower-income seniors from premium increases that would decrease their Social Security benefits. Conversely, the Income-Related Monthly Adjustment Amount (IRMAA) imposes surcharges on higher-income beneficiaries. For 2026, married couples filing jointly with a modified adjusted gross income (MAGI) exceeding $218,000 each face full surcharges, which can increase individual premiums from the standard rate to as high as $689.90.

## Timeline

### 2026-08-07: Medicare Part B premiums determined by program costs, not Social Security benefits

Medicare Part B premiums are determined by CMS based on anticipated program costs, not as a percentage of Social Security benefits. Adjustments like IRMAA and the hold harmless provision affect individual rates

2 sources. https://clstr.news/cluster/medicare-part-b-premiums-determined-by-program-costs-not-social-security-benefits

### 2026-07-23: US Medicare IRMAA surcharge raises premiums for high‑income couples

Medicare’s IRMAA surcharge, based on tax returns from two years earlier, fully applies to each spouse if joint MAGI exceeds $218,000, raising 2026 Part B premiums from $202.90 to $284.10 per person.

2 sources. https://clstr.news/cluster/us-medicare-irmaa-surcharge-raises-premiums-for-highincome-couples

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Cite as: US Medicare premium calculation and IRMAA surcharges. CLSTR, https://clstr.news/situations/us-medicare-premium-calculation-and-irmaa-surcharges