Social Security 2027 Cola Forecast Shows $240 IRMAA Charge Cuts $117 Raise
The social security 2027 cola forecast is not the problem in this example; the retiree’s 2026 Medicare bill is. A one-time Roth conversion pushed his MAGI to $140,000 and triggered a $240 monthly IRMAA surcharge that wiped out a $117 Social Security increase.
At 67, the single retiree drew $4,200 a month from Social Security, used modest IRA withdrawals and lived in a paid-off house. In 2024, he completed the Roth conversion before required minimum distributions begin, raising his usual MAGI from around $80,000 to roughly $140,000 for that tax year.
SSA Uses 2024 Returns
The Social Security Administration uses a tax return from two years earlier to set Medicare premiums, so the 2024 income spike fed into 2026 costs. The retiree landed in the third IRMAA tier, where a single dollar over the frozen near-$109,000 threshold applies the full surcharge for the entire year.
That premium hit changed the math on the COLA itself. The 2026 Social Security COLA was 2.8%, which added about $117 a month to a $4,200 benefit, or roughly $1,411 over a year. After the $240 monthly surcharge, the retiree’s check ended up $123 lower each month than expected.
IRMAA And The COLA
The standard 2026 Part B premium is $202.90, and the surcharge sits on top of that base amount. Consumer prices rose 3.8% year over year in April 2026, grocery prices climbed more than 3%, and energy costs jumped sharply over the same period, leaving less room for a premium increase to disappear into a cost-of-living adjustment.
For retirees using Roth conversions as a tax strategy, the timing matters as much as the amount. Splitting large conversions across multiple years can keep MAGI below the $109,000 threshold and avoid the full tier surcharge that can erase a raise before it reaches the bank account.
Roth Conversion Timing
That is the practical lesson from this example: a short-term income move can echo two years later in Medicare billing. Anyone planning a conversion before RMDs begin at 73 has to weigh the tax benefit against the premium tier it may trigger, because one dollar over the line changes the full-year charge.
