Affordability has a technical definition, and it is not the inflation rate. Economists measure it as a ratio: what a fixed basket of necessities costs, set against what a household actually earns. That distinction explains why a person can read that inflation has cooled and still watch rent, childcare, and insurance swallow the paycheck. Prices stopped climbing as fast. The gap between what things cost and what people are paid did not close.
The core measure is a ratio, not a price
The most widely used affordability measure in the United States is cost burden. The U.S. Census Bureau collects the inputs through the American Community Survey, and federal housing programs apply the threshold: a household spending more than 30 percent of gross income on housing is cost burdened, and a household spending more than 50 percent is severely cost burdened.
Notice what that measure does. It ignores the price of a house entirely. A $600,000 home is affordable to one buyer and impossible for another, and the number that decides which is true is income. Any serious affordability measure has income in the denominator.
Where the 30 percent line came from
The threshold is a policy convention rather than a law of household finance. It descends from older lending rules of thumb about what share of earnings could safely go to shelter, and it hardened into federal housing policy over the second half of the twentieth century. It is useful because it is consistent across decades, not because 31 percent is dangerous and 29 percent is safe.
The living wage approach builds the whole budget
The MIT Living Wage Calculator takes the opposite route. Instead of starting with a wage and asking what it buys, it starts with a county-level budget of food, childcare, health care, housing, transportation, other necessities, and taxes, then solves backward for the hourly wage a worker would need to cover it. The output is a required wage, not a comfortable one. It assumes no savings, no restaurant meals, no vacation, and no debt service.
Set that against the wage floor. The federal minimum wage has been $7.25 an hour since 2009, according to the U.S. Department of Labor. A full-time worker at that rate earns roughly $15,080 a year before taxes. There is no county in the country where the living wage calculation lands near that figure for a household with a child.
Why the Consumer Price Index does not answer the question
The Bureau of Labor Statistics publishes the Consumer Price Index, and it is frequently mistaken for an affordability measure. It is not. CPI tracks the average change in prices paid by urban consumers for a basket of goods and services. It reports the rate of change in prices. It says nothing about whether anyone can pay them.
Two things follow. First, inflation can fall to a low rate while the price level stays far above where it was five years earlier, because a lower rate of increase is still an increase. Second, CPI is an average, and averages hide distribution. A household that spends 45 percent of income on rent and 12 percent on childcare experiences a very different price environment than the index describes.
The income side of the ratio
Median household income sits at roughly $80,000, according to the U.S. Census Bureau’s 2023 estimate. The median home sale price ran roughly $400,000 to $420,000 in 2024 in figures from the National Association of Realtors and the Census Bureau. That puts the typical home at about five times median household income. In the 1980s the same ratio ran near three.
That shift is the whole argument in one number. Nothing about the house changed. The relationship between what houses cost and what people earn changed, and it changed by a factor large enough to reorganize who can buy one.
A worked example
Take a household earning $80,000 gross, which is close to the national median. Monthly gross income is about $6,667.
Apply the 30 percent housing threshold and the household has $2,000 a month for rent or mortgage, taxes, and insurance. Add one child in center-based childcare, which Child Care Aware puts commonly in the range of $10,000 to $17,000 or more per year, and that is another $833 to $1,417 a month. Add the worker share of an employer family health premium, which KFF put at $6,850 in its 2025 Employer Health Benefits Survey, or about $571 a month.
Three line items now consume $3,404 to $3,988 of a $6,667 monthly gross. That is 51 to 60 percent of income before a single dollar goes to federal or state taxes, food, transportation, student loans, or retirement. The household is not overspending. It is arithmetically short.
What to actually watch
Anyone trying to read the affordability picture should track category ratios rather than the headline inflation print. Housing cost as a share of median income. Childcare cost as a share of median income. Worker premium share as a share of median income. Each one is a fraction with earnings on the bottom, and each has moved in the same direction for two decades.
The figures live in separate federal releases on different schedules, which is part of why the pattern is easy to miss. Fight For A Living Wage maintains a running collection of the affordability figures in one place, which saves the work of assembling them by hand from four agencies.
The measurement question matters because it determines the policy question. If affordability were a price problem, the fix would be price controls. If it is a ratio problem, and every serious measure treats it as one, then the answer has to move the denominator too.