Cost-of-living indexes explained: RPP, C2ER, and more

BEA Regional Price Parities (RPP)

RPPs are published annually by the Bureau of Economic Analysis. They measure the price level of an area relative to the U.S. average (set to 100) using price data for consumption goods and services, including housing. ReloMath uses the 2022 data year.

Coverage: All metropolitan statistical areas (MSAs) and states.
Methodology: Combines CPI price quotes and ACS housing rents with expenditure weights from BEA personal consumption expenditures and ACS housing expenditures. See the BEA 2022 release technical notes (historical methodology).
Lag: Typically 1-2 years behind present day.
Best for: Apples-to-apples salary and cost-of-living comparisons between any two U.S. metros.

ACCRA/C2ER Cost of Living Index

Published quarterly by the Council for Community and Economic Research, this index surveys prices in participating cities for a basket of items including groceries, housing, utilities, transportation, healthcare, and miscellaneous goods.

Coverage: Varies — typically 200-300 urban areas that voluntarily participate.
Methodology: Self-reported price surveys by local chambers of commerce.
Best for: Detailed category-level comparisons when both cities are well-covered.
Limitation: Participation bias — cities that participate tend to be larger or more research-oriented.

MIT Living Wage Calculator

This tool calculates the minimum wage needed to cover basic expenses by family type in any county or metro. It is not a cost-of-living index but rather a minimum-income benchmark.

Best for: Understanding poverty thresholds and minimum living standards.
Not for: Middle-income salary equivalency comparisons.

HUD Fair Market Rents (FMR)

HUD FMRs are 40th-percentile gross-rent benchmarks for standard-quality rental housing. ReloMath retains FY2024 2-bedroom values. They are not median rents, current listings or individual leases.

Coverage: HUD-defined metropolitan rent areas and nonmetropolitan counties; these boundaries can differ from BEA metros.
Best for: Historical rental-market context; use a current lease for personal budgeting.
Limitation: Housing only — does not cover other cost-of-living categories.

Which index should you use?

• Total cost-of-living comparison: BEA RPP
• Rent budgeting: Your actual lease; HUD FMR provides separate historical context
• Category-level detail (groceries, utilities, etc.): C2ER, if your cities are covered
• Minimum living wage: MIT Living Wage Calculator

ReloMath uses BEA RPP as the primary index and HUD FMR for rent benchmarks. The methodology links the dated source tables and identifies selected areas checked. Overall RPP already includes housing; do not add FMR or your lease to an RPP salary figure.