Methodology

Home Payment Atlas is a planning tool. We aim to be transparent about every number so you can judge how well it fits your situation. The most important distinction on this site is between measured data (real values we read from Zillow) and calculated assumptions (figures this tool estimates and that you can change).

Home-value data (measured)

• Source: Zillow Research Home Value Index (ZHVI), state level, smoothed and seasonally adjusted.
• Typical value is the middle price tier (35th–65th percentile). Starter uses the lower tier and higher-budget the upper tier.
• We also surface single-family, condo/co-op, and bedroom-count values where available.
• We extract the latest available month for each state (currently 2026-05).
• Values are Zillow's estimates and may not match current listings, appraisals, or lender valuations.

Mortgage math (calculated)

Monthly principal and interest use the standard fixed-rate formula:

M = P · r(1 + r)ⁿ / ((1 + r)ⁿ − 1)

• P = loan principal (price − down payment)
• r = monthly interest rate (annual rate ÷ 12)
• n = number of monthly payments (years × 12)
• If the interest rate is 0%, we divide the loan evenly across all payments.

Default assumptions (calculated)

• Interest rate: 6.5% (editable)
• Property tax: 1.1% of home value per year by default. State pages use a state-specific effective rate (see below), and you can always enter your own dollar amount.
• Homeowners insurance: 0.35% of home value per year, unless you enter a dollar amount
• PMI: 0.5% of the loan per year, applied only when the down payment is under 20%
• Closing costs: about 3% of the price, included in "estimated cash needed"
• Income needed: based on a 28% housing-cost-to-income guideline

State-specific property tax

On state pages, the calculator prefills an approximate effective property-tax rate for that state (annual property tax as a percentage of home value), rather than a single national figure. Please read these as planning estimates, not your actual bill:

• State rates are planning estimates. They are statewide approximations compiled from public data, not official figures for your property.
• County and city rates vary widely within every state — two homes of the same value in the same state can owe very different amounts.
• Exemptions and assessments vary. Homestead exemptions, senior or veteran exemptions, assessment caps, and how often a county reassesses can all change what you actually pay.
• Enter your local figure for accuracy. For a realistic result, replace the default with your county's effective rate or your actual annual property-tax dollar amount.

States without a specific rate fall back to the 1.1% national default.

Affordability labels

When you enter income, we compare your total housing payment to gross monthly income: up to 28% is Comfortable, up to 36% Manageable, up to 43% Tight, and above that Stretching. These are general guidelines, not lending decisions, approvals, or qualifications.

Limitations

• Rent comparisons use Zillow ZORI rent data and are available on our city pages; they are snapshots, not a complete rent-vs-buy decision (which also depends on maintenance, time horizon, opportunity cost, appreciation, and transaction costs).
• We cover all states plus a curated first set of city pages. We add cities deliberately rather than generating every place, to keep each page genuinely useful.
• Taxes, insurance, PMI, and rates vary widely by location, lender, and borrower — always confirm with the relevant professional.