Our Data Methodology & Calculation Models

City baselines on Cost of Parenting are planning models, not invoices. We blend national research with metro-level price signals so families can compare places on a consistent footing.

• USDA Expenditures on Children — category shares and life-stage patterns for food, clothing, healthcare, childcare, and related child-rearing costs.
• BLS Consumer Price Index (CPI) — regional and category inflation updates that keep older survey vintages aligned with current purchasing power.
• Local childcare rate reports — state and metro daycare, preschool, and after-school price surveys that anchor infant-through-school-age care stacks.
• MIT Living Wage benchmarks — county-level living-wage and family-budget context used to cross-check housing, food, and transportation floors.

Where a metro lacks a fresh primary survey, we interpolate from peer cities and national category weights, then flag figures as illustrative planning estimates.

Each city starts from a school-age / elementary reference baseline (annual USD by category). Monthly stage stacks for infant, toddler, and school-age care feed that baseline; forecasts then scale costs by child age and household size.

Age tiers. Costs are adjusted relative to the elementary reference (1.0):

• Infant (0–2) — about 1.4× the reference year (full-day care, diapers, and formula).
• Toddler (2–4) — about 1.25× as preschool remains expensive while supply spend eases.
• Elementary (5–12) — reference band (1.0) used for published annual category mixes.
• Teen (13–17) — about 1.15× as food, clothing, activities, and transport rise again.

Family size modifiers. Household totals are not a simple per-child multiply. Shared costs (housing uplift, some transport and utilities) create economies of scale:

• 1 child — modeled at roughly +27% versus a pure per-category “average child” split, because fixed family premiums (especially housing) load onto a single dependent.
• 3+ children — about −24% efficiency per additional child relative to stacking full one-child totals, reflecting shared rooms, bulk food, and reused gear.

Interactive calculators apply these modifiers on top of the local baseline; Premium forecasts extend the same logic across an 18-year horizon.

Historical USDA and survey vintages are not left in their original dollar years. We index category baselines forward using BLS CPI series (all-items and relevant child-cost components such as childcare, food at home, and medical care) to express figures in 2026 dollars.

When a metro’s local childcare or rent report is newer than the national survey year, we prefer the local vintage and only inflate residual categories. Published city pages show a data updatedAt stamp so you can see the model vintage at a glance.

Inflation indexing keeps multi-city comparisons fair; it does not predict future price paths. Premium multi-year outlooks may apply an explicit forward inflation assumption on top of today’s indexed baseline — always labeled separately from the 2026 present-day stack.

See the methodology applied on live city guides, or open a side-by-side comparison tool:

Questions about a specific metro or data vintage? Contact us or read more about Cost of Parenting.