Monthly Social Security and Supplemental Security Income (SSI) benefits for more than 66 million Americans will increase by 2.0 percent in 2018. The 2.0 percent cost-of-living adjustment (COLA) will begin with benefits payable to more than 61 million Social Security beneficiaries in January 2018. Increased payments to more than 8 million SSI beneficiaries will begin on December 29, 2017.
The table below provides an overview of the changes from 2017 to 2018.

Source: https://www.ssa.gov/news/cola/