Methodology & data sources

This is a market-discovery tool built on public and research data with transparent, editable assumptions. Here is exactly where the data comes from, how every number is produced, and what we deliberately leave to a detailed calculator.

Data sources at a glance

Roles of each source

Zillow Research supplies housing-market texture: home values by tier (ZHVI bottom/mid/top and by bedroom count) and the rent index (ZORI). We use only Zillow's aggregate research datasets — never listings, photos, or individual property details — and Zillow does not endorse this site. The U.S. Census Bureau is the backbone for official public-data context: household income (ACS), population, FIPS codes, and the state/county geography that draws the map. HUD Fair Market Rents can supplement rent where useful. Home Payment Atlas is the destination for detailed mortgage and payment customization — we link there rather than duplicating that math.

Derived insights (not copied tables)

We combine sources into original, directional signals: a starter-home affordability score (Zillow bottom-tier value vs income), a median- and family-home affordability score (mid-tier and 3-bedroom values), rent-vs-income pressure (ZORI vs income), and — on the roadmap — a Buyer Opportunity Score and price-cut opportunity index. Our state rent figure is itself derived: the median of Zillow city-level ZORI within each state.

How the monthly payment is calculated

We take the home value for the chosen tier, subtract a 10% down payment, and amortize the loan at a 6.70% rate over 30 years for principal & interest. We add property tax (1.1%/yr of value), homeowners insurance (0.45%/yr), and PMI (0.6%/yr of the loan when down payment is under 20%).

How income needed & the affordability score are calculated

Income needed scales the monthly payment so housing is about 28% of gross income. The 0–100 score compares income with that income needed: a ratio of 0.4 or below scores 0, 1.6 or above scores 100, linear in between.

Market-signal layers (data roadmap)

The Buyer Opportunity, Market Heat, and Price-cut layers depend on Zillow inventory, price-cut, days-to-pending, and market-heat datasets that are not yet imported. Until then these layers show an honest "data coming soon" state — we never publish placeholder market numbers.

What this site does not know

It does not know your credit, exact local tax rate, HOA dues, insurance quote, loan program, or the rate you'll be offered. It is not a pre-approval and not advice. For any real decision, customize the scenario on Home Payment Atlas and confirm with a lender.

Customize on Home Payment Atlas

Home Payment Atlas is the companion calculator for detailed mortgage math. Use the full mortgage calculator to adjust every input, and review the Home Payment Atlas methodology.

About these estimates & data sources

Home values and rents reflect Zillow Research data (ZHVI and ZORI, 2026-05). Household income reflects U.S. Census ACS data. All figures are estimates for general comparison, not appraisals or quotes — confirm details before relying on them.

Home values and rent: Zillow Research (ZHVI, ZORI), 2026-05. Geography and FIPS codes: U.S. Census Bureau (Cartographic Boundary Files). Household income: U.S. Census ACS. Detailed payment math: Home Payment Atlas. Zillow does not endorse this site.

Figures are educational estimates only and are not financial, legal, tax, mortgage, or real-estate advice, and not a loan offer. Verify every number with lenders, agents, tax authorities, and official sources. See our methodology and terms & disclaimer.