The Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W), updated monthly by the Bureau of Labor Statistics (BLS), is the measure that can trigger a benefit increase. The Social Security cost-of-living adjustment (COLA) is based on the growth in the index from the highest third calendar quarter average CPI-W recorded (most often, from the previous year) to the average CPI-W for the third calendar quarter of the current year. If the CPI-W triggers a COLA, the COLA becomes effective in December of the current year and is payable in January of the following year. (Social Security payments always reflect the benefits due for the preceding month.) What Is the COLA to Be Paid in January 2019? As a result, an automatic COLA in January 2010 was not triggered and the third quarter of 2008 remained the cost-of-living computation quarter (i.e., the benchmark) used to determine if a COLA would be payable in January 2011. Other Programs

Social Security COLAs trigger increases in other programs. Supplemental Security Income (SSI) benefits and railroad retirement "tier 1" benefits (equivalent to a Social Security benefit) are increased by the same percentage as the Social Security COLA or are held constant when a COLA is not paid to Social Security beneficiaries. Although COLAs under the Civil Service Retirement System (CSRS) and the federal military retirement system are not triggered by the Social Security COLA, these programs use the same measuring period and formula for determining their COLAs.
To compensate for the effects of inflation, Social Security recipients usually receive an annual cost-of-living adjustment (COLA). According to parameters outlined in the Social Security Act (42 U.S.C. 415(i)), a 2.8% COLA is payable in January 2019. For a retired worker receiving the average monthly benefit amount of $1,422, the COLA will result in a $39 increase in Social Security benefits (after final rounding down to the nearest dollar for a total of $1,461).
Social Security COLAs are based on changes in the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W), updated monthly by the Department of Labor's Bureau of Labor Statistics (BLS). The COLA equals the growth, if any, in the index from the highest third calendar quarter average CPI-W recorded (most often, from the previous year) to the average CPI-W for the third calendar quarter of the current year. The COLA becomes effective in December of the current year and is payable in January of the following year. (Social Security payments always reflect the benefits due for the preceding month.)
If there is no percentage increase in the CPI-W between the measuring periods, no COLA is payable. No COLA was payable in January 2010, January 2011, or in January 2016.
The January 2019 COLA will also be applied to Supplemental Security Income (SSI) and railroad retirement "tier 1" benefits, among other changes in the Social Security program. Although COLAs under the federal Civil Service Retirement System (CSRS) and the federal military retirement program are not triggered directly by the Social Security COLA, these programs use the same measuring period and formula for computing their COLAs. As a result, their recipients will receive a similar COLA payable in 2019.