Cost of living and the living wage: what a salary actually buys

A salary is only half a number. The other half is where you spend it. I have watched people turn down a $90,000 offer in one state and celebrate a $90,000 offer in another, as if the two figures meant the same thing — they do not, and the gap between them is measurable. When people search for a cost of living calculator, they are usually asking one of two very different questions, and confusing the two produces bad decisions. Let me separate them, show you how each number is actually built, and run a worked example with real federal data.

Two different questions hiding in one search

A cost-of-living index answers: “How do prices here compare with prices there?” It prices the same basket of goods and services in two places and reports the ratio. It says nothing about whether you earn enough — only about what things cost relative to somewhere else.

A living wage answers a different question: “What must a household in this specific place earn to cover a basic budget?” It is built from the bottom up — actual local costs for food, housing, childcare, healthcare, transport and taxes, for a specific household size. When someone uses a living wage calculator, they are checking adequacy, not comparison.

A cost of living comparison calculator works with the first idea. Keep the two apart and both become useful; blur them and you end up comparing a salary against a number that was never designed for your household.

How a cost-of-living index is built

Start with the basket. The US Bureau of Labor Statistics builds the Consumer Price Index from categories of everyday spending, weighted by how much households actually spend on each. Housing is the giant: roughly 44% of the whole basket, with shelter — rent and its homeowner equivalent — at about 36% on its own (BLS relative-importance weights, December 2024). Food is around 14%, energy around 6%, and the rest is spread across transport, healthcare, clothing and everything else. That weighting is the single most important fact about any index: an index is mostly a housing index wearing a coat.

The Bureau of Economic Analysis then takes price data and publishes Regional Price Parities (RPPs): each state’s overall price level as a percentage of the national level, which is set to 100. For 2024, BEA put California at 110.7 — prices 10.7% above the national level — with Hawaii at 110.0 and New Jersey at 108.8 at the top, and Arkansas (86.9) and Mississippi (87.0) at the bottom. And here is the detail that matters most: California’s RPP for housing rents alone was 154.3. The overall gap between states looks modest; the rent gap is enormous.

The worked example: what a salary buys in three states

Converting a salary between states is one division. Take the salary, divide by the price level where you are, multiply by the price level where you are going:

Equivalent salary = salary × (destination RPP ÷ current RPP)

Computed from BEA Regional Price Parities, 2024 (US average = 100). These are state-level averages — a specific metro area will differ.

Read the first row slowly. A $90,000 salary in Texas buys the same overall basket as about $102,606 in California — you need a raise of roughly 14% just to stand still. The reverse row is the mirror image: the Californian who keeps a $90,000 salary while moving to Texas gains the equivalent of about $11,057 of extra purchasing power without negotiating a cent.

Now the honesty check, because the index flattens the thing that dominates real budgets. Median gross rent for a two-bedroom home, from the Census Bureau’s American Community Survey (2020–2024), is $2,103 a month in California against $1,395 in Texas — a gap of $708 every month, or about 51%. If rent is a big share of your spending, the headline 14% index gap understates your real gap. If you own your home outright, it overstates it. The index describes the average basket; your basket is yours.

How a living wage is built

The reference model here is the MIT Living Wage Calculator, and its method is the opposite of an index: no ratios, just budgets. For each county and for a set of household types — a single adult, two adults with one or two earners, with and without children — it prices the actual local cost of:

• Food, from the USDA’s low-cost food plan;
• Housing, from HUD fair market rents for the area;
• Childcare, where children are in the household — often the second-largest line after housing;
• Healthcare, transportation and other necessities, from federal expenditure data;
• Taxes, because the wage quoted is a gross wage — it must cover the tax bill too.

Add the lines, divide by the hours of work, and you have the living wage for that household in that county. Note what it is not: it is not the minimum wage. The federal minimum wage is a legal floor, $7.25 an hour, unchanged since 2009 — a political number, not a budget. A living wage figure is a measurement, updated as costs change, and in most US counties it sits well above the legal minimum. That gap is information, whichever side of a hiring decision you sit on.

Sources: Bureau of Economic Analysis, Regional Price Parities by State, 2024 (California 110.7, Texas 97.1, Mississippi 87.0; California rents 154.3). US Census Bureau, American Community Survey 2020–2024, median two-bedroom gross rent (California $2,103, Texas $1,395). US Bureau of Labor Statistics, CPI relative-importance weights, December 2024. Living wage method: MIT Living Wage Calculator methodology (county budgets by household type). Salary equivalences recomputed from the RPP ratios for this article.