The C2ER Cost of Living Index provides city-to-city comparisons of key consumer costs. C2ER COLI data are recognized by the U.S. Census Bureau, US Bureau of Labor Statistics, and the President's Council of Economic Advisors. Data and methodology are described in detail and completely transparent to users. Both data and methodology are reviewed by an advisory board composed of academic researchers and government officials. Available datasets: Current cost of living index (available in PDF and Excel format); Historical cost of living index (COLI historical), with coverage from Q1 1990 to the present; and County-level cost of living index, covering all 3,114 counties in the United States. Also includes a calculator, which allows the user to select a combination of areas and calculate comparable income between two places.