Methodology & Sources

How we build the numbers.

Every figure on this site comes from a public, sourced dataset. We do not invent estimates. We do not adjust upward or downward based on what we wish were true. When sources disagree, we say so. When data is older than we'd like, we say that too.

The eight pillars

MIT Living Wage Institute
State and county-level cost-of-living estimates for different family compositions. Updated February 2026, expressed in December 2025 dollars. We use this as our baseline reference for housing, food, and transportation cost indices.
USDA Expenditures on Children by Families
Age-stratified per-child cost data — food, clothing, healthcare, transportation, school/activities, and miscellaneous. Teen years (15–17) are the most expensive at roughly $13,900 per year per child before housing. Infant years (0–2) average about $7,140.
USDA Thrifty / Low-Cost Food Plans
Adult food cost baseline of $425/month, January 2025 update. Household-size adjustments per USDA methodology (1-person households add 20% per capita; 4-person are baseline; 7+ subtract 10%).
Experian Q4 2025 Auto Finance Report
Average new car payment of $767/month, used $537/month. Loan terms span 60–84 months. We use $700 (new) and $510 (used) as conservative baselines.
ValuePenguin 2026 Auto Insurance Report
State-by-state full-coverage rates. Range: $118/month (New Hampshire) to $358/month (Nevada). Maryland, Connecticut, Florida, and Louisiana all exceed $300/month.
Peterson-KFF Health System Tracker
State-level adults with medical debt, healthcare premium and deductible benchmarks. Per-capita health spending was $15,474 in 2024, up 7.2% year-over-year.
HHS-ACF Childcare Market Rate Survey
Childcare prices by age, state, and care setting. The federal "affordable" threshold is 7% of household income. The District of Columbia has the most expensive infant care in the nation at roughly $2,400/month.
BLS Consumer Expenditure Survey
Utilities (electric, gas, water, internet, mobile), fuel, household maintenance baselines. State-indexed.

How we calculate

Housing uses a $1,200/month state-indexed baseline scaled by household size — 1.0× for 1–2 people, 1.55× for 3–4, 2.05× for 5–6, 2.45× for 7+. Owners pay an 18% premium to cover mortgage interest, property tax, insurance, and maintenance.

Adult food uses USDA's Low-Cost Food Plan ($425/month per adult), state-adjusted by 0.9× the cost-of-living index.

Per-child direct costs are calculated individually for each child based on their age. An infant draws ~$595/month direct costs. A teenager draws ~$1,560/month direct costs — and that's before any driving expenses are added.

Childcare uses HHS-ACF state market rates for infants, toddlers, and preschool. Children aged 6–11 are assumed to be in school but accumulate after-school care equivalent to 35% of full preschool rates.

Transportation sums car payments + state-specific auto insurance + $280/vehicle/month for fuel and maintenance. A driving teen adds $380/month: this covers the insurance bump from adding a teen driver, their gas, and a maintenance share. The $380 figure is conservative — many families experience double that.

Healthcare models four insurance scenarios. Employer-sponsored uses the KFF average employee share (17% individual, 27% family) plus expected out-of-pocket. Marketplace uses CMS benchmark silver-plan premiums. Medicaid assumes nominal cost. Uninsured assumes 40% of expected medical need is paid out of pocket.

Single parents receive a 12% surcharge on all child-related costs. This reflects the well-documented reality that without a co-parent to share childcare, time, and household labor, costs effectively rise.

Taxes use a blended effective rate based on state cost index — 19% for low-cost states, 21% for mid-cost, 24% for high-cost. This includes federal income tax, state income tax, FICA (Social Security + Medicare), and typical state-level taxes.

What this tool does not do

We don't model wealth or savings. We don't model investment income or retirement contributions. We don't include college tuition. We don't include emergency funds. The figures here represent the cost of currently living — not the cost of preparing for the future, recovering from setbacks, or building wealth across generations.

That gap — between covering basic needs and actually thriving — is itself one of the most important policy questions of our time.

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