The 2027 Social Security cost-of-living adjustment is projected at 3.6%, according to The Senior Citizens League, an advocacy group. That would be 0.8 percentage points higher than the 2026 COLA and the largest increase since 2023, adding an estimated $60 to $75 per month for the average retiree. Rising Medicare Part B premiums would partly offset the increase. More than 75 million Americans receive Social Security benefits. The Social Security Administration will announce the official COLA next month, based on the year-over-year change in third-quarter inflation measured by the Consumer Price Index for Urban Wage Earners and Clerical Workers, or CPI-W. The latest July CPI-W reading was 3.3%, although it does not directly determine the final adjustment. The projection is below earlier estimates this year after a truce in the war in Iran helped stabilize gas prices, while renewed fighting could push energy costs higher during the third quarter of 2026.