How is a COLA calculated?
The Social Security Act specifies a formula for determining each COLA. According to the formula, COLAs are based on increases in the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W). CPI-Ws are calculated on a monthly basis by the Bureau of Labor Statistics.
A COLA effective for December of the current year is equal to the percentage increase (if any) in the CPI-W from the average for the third quarter of the current year to the average for the third quarter of the last year in which a COLA became effective. If there is an increase, it must be rounded to the nearest tenth of one percent. If there is no increase, or if the rounded increase is zero, there is no COLA for the year.
COLA Computation
The last year in which a COLA became effective was 2020. Therefore the law requires that we use the average CPI-W for the third quarter of 2020 as the base from which we measure the increase (if any) in the average CPI-W. The base average is 253.412, as shown in the table below.
Also shown in the table below, the average CPI-W for the third quarter of 2021 is 268.421. Because this average exceeds 253.412 by 5.9 percent, the COLA effective for December 2021 is 5.9 percent. The COLA calculation, with the result rounded to the nearest one-tenth of one percent, is: