How to Compare Cost of Living Across Counties

Introduction

The gap between the most and least expensive U.S. counties is wider than most people realize. The priciest county costs roughly 3.4x the cheapest on a cost-of-living basis (Council for Community and Economic Research, 2024) — a difference that dwarfs the salary gaps that often drive relocation decisions.

"A salary that feels like a raise in one county can be a pay cut in another. The single biggest mistake relocators make is comparing salaries instead of comparing what's left after rent, taxes, and groceries." — Cost-of-living researcher

This guide breaks down how to compare counties on a true cost-of-living basis — for relocation, for investment underwriting, or for sizing a market for a new business.

Cost of Living Breakdown by County

Housing

Housing is the single largest line item and the largest source of county variance. The median rent in the priciest U.S. county runs more than 3x the median in the cheapest (Zillow Research, 2024).

Key data:

• Median rent for a 2-bedroom unit
• Median home value and price-to-income ratio
• Property tax rate — varies from under 0.5% to over 2% of home value by county (Tax Foundation, 2024)

Transportation

Counties with limited transit and long commutes carry higher transportation costs — often $1,000+ per month per household in car-dependent exurbs (Bureau of Economic Analysis, 2024).

Groceries & Goods

Grocery prices vary by roughly 15–20% across U.S. metros (C2ER, 2024). Sales tax — which varies from 0% to over 9% by county — compounds the difference.

Healthcare

Healthcare premiums and out-of-pocket costs vary by 20–30% across counties, driven by local provider concentration and insurance market structure (KFF, 2024).

Taxes

A county's effective tax burden is a composite of property tax, state income tax, and sales tax. The Tax Foundation (2024) publishes a state-local tax burden comparison; combined with county property tax rates, it gives a true effective rate.

Utilities

Utility costs vary by climate and grid mix. Heating-heavy northern counties and cooling-heavy southern counties each run 15–25% above the national average (U.S. Energy Information Administration, 2024). Insurance — increasingly a utility-like fixed cost — has risen 20–40% in high-risk counties (Insurance Information Institute, 2024).

Key Terms

• COLI (Cost of Living Index): A composite comparing the cost of housing, groceries, utilities, transportation, and healthcare in a county against the national average (100). A COLI of 120 means 20% more expensive than average.
• Effective Tax Rate: Total state, local, and property taxes paid as a percentage of household income. A more accurate measure than marginal rate for relocation comparison.
• Price Parity (RPP): The Bureau of Economic Analysis Regional Price Parities index — compares the price level of goods and services in a metro/county against the national average.
• Housing Burden: The share of household income spent on housing. Above 30% is considered cost-burdened; above 50% severely burdened.
• RPP: Bureau of Economic Analysis Regional Price Parities — a federal alternative to the private COLI, reported annually by metro area.

5-Step Comparison Method

1. Pull the county report for both counties to get median income, rent, and home value side by side.
2. Compute housing burden — median rent divided by median monthly household income.
3. Add the effective tax rate from the Tax Foundation state-local burden plus the county property tax rate.
4. Adjust salary or expected rental income by the COLI or RPP for each county.
5. Compare the remainder — what's left after housing, taxes, and basic goods — to make the apples-to-apples call.

Sources

1. Council for Community and Economic Research (C2ER), Cost of Living Index, 2024.
2. U.S. Bureau of Economic Analysis, Regional Price Parities, 2024.
3. Tax Foundation, State and Local Tax Burden Rankings, 2024.
4. Zillow Research, Observed Rent Index, 2024.
5. National Association of Realtors (NAR), Affordability Index, 2024.
6. Kaiser Family Foundation (KFF), Healthcare Costs by Region, 2024.
7. U.S. Energy Information Administration, Residential Energy Prices, 2024.
8. Insurance Information Institute, Homeowners Insurance Trends, 2024.