Methodology and limitations

Data: Zillow Research ZHVI and ZORI, as of 2026-09-30. These are typical home-value and rent indexes, not sale-price or rent medians for a matched set of properties.

The selected ZIP codes have data in both series. ZHVI here covers single-family/condominium homes; ZORI also includes multi-family rental stock. Combining them produces a screening proxy, not an observed average cap rate or return. Rankings apply only to the selected sample.

Default model: 20% down, 6.5% annual interest, 30-year amortization, 3% closing costs, state-average effective property tax, insurance at 0.5% of value/year, 5% vacancy and 8% repair/CapEx reserves. HOA and management default to $0 in the regional model. State tax rates are approximate, not tax quotes; their reference year has not been verified. Local assessments, reassessment after sale, insurance quotes, flood coverage, utilities, repairs and management may materially differ.

Displayed NOI and cap rate include the selected repair/CapEx reserve. DSCR is this NOI divided by annual principal and interest; lender definitions differ. The model excludes appreciation, income tax, selling costs and some property-specific expenses. It is an estimate, not a guarantee or financial advice.

The extension reads supported listing fields. Missing purchase price/rent pauses the calculation; unknown tax/insurance/HOA is explicitly marked as assumed. Manually verify every input before making a decision. The website and extension use the same JavaScript calculation engine.