She Is Going Part-Time at 66. Half the Hours, Half the Pay, and a 2027 Medicare Premium Priced on the Full Salary Until She Tells Social Security in Writing
Going part-time at 66 cut her paycheck in half, but Medicare kept billing her like nothing changed, and the reason comes down to a two-year gap in Social Security's records that most people never know exists until they see the…
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She is 66 and already on Medicare. In 2026 she cut her schedule from five days a week to two or three. Her paycheck fell by 50% almost overnight. Her Medicare premium stayed where it was, and her 2027 bill is on track to stay there too.
The cause is the two-year lookback. Social Security sets the income-related surcharge, IRMAA, from tax data two years old. That means 2027 premiums generally look back to 2025, when she still earned her full salary. The Centers for Medicare & Medicaid Services (CMS) says IRMAA affects roughly 8% of Part B enrollees. Under 2026 rules, a single filer with income at or below $109,000 ($218,000 joint) pays only the standard premium and has nothing to fix. Anyone whose income dropped from well above that line to near or below it may be paying more than necessary unless Social Security uses the newer income figure.
Medicare Is Still Billing Her Full-Time Salary
Here are the latest numbers. Her 2025 MAGI was $180,000. After the schedule change, she projects 2026 MAGI of $90,000. Unless she asks for a new determination, Social Security starts her 2027 calculation from the $180,000 IRS figure. The system looks back by design.
At $180,000, a single filer pays a Part B surcharge of $324.60, for a total Part B premium of $527.50 a month. She also pays a Part D surcharge of $60.40 on top of her plan premium. At $90,000, her Part B premium is the standard $202.90, with no Part D surcharge. The difference is $385 a month, or $4,620 over 12 months. The Medicare Trustees currently estimate the 2027 standard Part B premium at $209.50.
Going Part-Time Breaks the Two-Year Lookback
Social Security treats work reduction as a qualifying change in circumstances. Its own examples include partial retirement and moving from full-time to part-time work. That makes her case unusually clean. Her 2025 return was accurate. It simply no longer describes what she earns. Once she documents the reduction, Social Security can make a new initial determination using her more recent income.
Other qualifying events include marriage, divorce or annulment, the death of a spouse, work stoppage, loss of income-producing property, loss or reduction of pension income, and certain employer settlement payments. A voluntary jump in income never qualifies. A Roth conversion or home sale that pushed MAGI up stays on her record, however large it was.
She Can File Before Her 2026 Tax Return Exists
She can prove the lower income now. Form SSA-44 lets her report an income drop that has already happened or one she expects, using an estimate of her 2026 MAGI. Her evidence can be an employer statement showing reduced hours, old and new pay stubs, or her own statement under penalty of perjury about the work change. After she files her 2026 return, Social Security checks the estimate against her actual income and adjusts if needed.
Half the Pay Can Still Trigger a Surcharge
Wages are only one input. MAGI for IRMAA equals adjusted gross income (Form 1040, line 11) plus tax-exempt interest (line 2a). Municipal bond interest that feels tax-free still counts. Her MAGI can stay above the first threshold even with $90,000 in wages if 2026 also brings:
- A large IRA withdrawal or Roth conversion
- Pension income or the taxable share of Social Security benefits
- Capital gains, interest, or dividends
The work reduction opens the door, and her actual MAGI determines what happens next. Timing matters too: her 2026 income also sets her 2028 premium. If she converts Roth assets before December 31, the income lands directly in that calculation, so she should run it against the threshold first.
What to Send Social Security Now
- File SSA-44 and check “Work Reduction.” Enter the date her hours dropped, her filing status, and her estimated 2026 MAGI. She can upload it through her my Social Security account, mail or fax it to a local office, or call 800-772-1213. If her 2027 IRMAA notice still shows the full salary, she should respond to it the same way.
- Attach proof: an employer letter confirming the new schedule, plus one pay stub from before the change and one from after.
- Send Social Security her signed 2026 tax return once she files it. That confirms the estimate instead of leaving it open to reversal.
One conversation with her boss cut her workweek in half. Medicare’s income record runs two years behind. An hourly cut is one of the few events that lets her pull that record forward, but only after she asks Social Security for a new determination (IRMAA is one of several Medicare surcharges that quietly increase retiree costs, and we mapped out the rest in a free guide to Medicare’s hidden bills.)
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Gerelyn Terzo is the author of dividend investing handbook "Dividend Investing Strategies: How to Have Your Cake & Eat It Too." A veteran financial journalist, she covers agri-finance for outlets like Global AgInvesting and the broader stock market and personal finance for 24/7 Wall Street. She began at CNBC and later helped launch Fox Business in New York. Gerelyn currently resides in Woodland Park, Colorado and dabbles in nature photography as a hobby.
