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See why January's Social Security check can shrink

Medicare withheld more from the deposit. The two-year MAGI lookback and the IRMAA cliff are why. Screenshot the decoder. Then two questions for this household.

Retirement Tax Radar

Why January's check can shrink

Medicare took more from the Social Security deposit. It is using a tax return from two years ago (MAGI lookback), not this year's paycheck.

Income year2024 MAGI (line 11 plus line 2a)
Premium year2026
LookbackTwo years. 2024 income writes the 2026 premium.
Single / widow line$109,000
Couple line$218,000
IRMAA cliff$1 over is the full first-tier extra for twelve months, not a $1 surcharge.
$1 over costs$1,148.40 per person
$2,296.80 if both on Medicare

They often take the extra from your Social Security deposit. That is why January feels lighter. Hold harmless does not cover this extra.

Educational estimate. CMS Nov 14 2025. Not tax, legal, or investment advice.

Now see whether this household crossed the line.

Married filing jointly on the return?

Medicare's first income line is $218,000 for a couple, $109,000 if not. "No" uses the individual line: single, head of household, or qualifying widow(er). Married filing separately is a different table. Use the full checker after the result if that is you.

Form 1040: line 11 (AGI) plus line 2a (tax-exempt municipal-bond interest). A close number is fine. In 2026, Medicare uses the 2024 return. Not this year's paycheck.

What counts?

AGI is wages, IRA withdrawals, the taxable part of Roth conversions, pensions, capital gains, and similar, minus adjustments. Then add tax-exempt interest. Do not use "total income" (line 9). That is before adjustments.

Educational estimate. Not tax, legal, or investment advice. Full January guide.