Home Value Estimator (AVM-Lite)
HouseCanary's AVM API is enterprise-priced. Zillow's Zestimate doesn't expose an API. ATTOM's product is licensed. The directional question — "is this home worth the asking price?" — is answerable from the county-level median price-per-square-foot and a few hedonic adjustments. The output below is that math, transparently, free.
Pick a state and county to see the estimate.
How this works
- Base = county median price-per-sqft × your sqft. Redfin Data Center publishes county PPSF; we read it directly. Floor at $60/sqft to suppress mobile-heavy exurban markets where the headline median misrepresents stick-built stock.
- Bedroom adjustment ±4.5% per bed from a 3-bedroom baseline (the U.S. median). NAHB hedonic studies bracket this at 3-6%; we use 4.5%.
- Bathroom adjustment ±3.5% per bath from a 2-bath baseline. Bath additions return less than bed additions in resale.
- Year-built adjustment. Brand-new (under 5 yrs) gets +8%; 5-15 yrs +3%; 15-30 flat; 30-50 -4%; 50-80 -8%; 80+ -14%. Reflects average condition and code-current expectation, not historic-charm premium.
- Confidence band ±15-18%. Free-data AVMs cannot resolve lot size, view, condition, renovation, layout quality, or pool/garage premium. Real appraisers narrow this to ±5% with a comp set.
- Use cases. First-pass screen ("is this priced right enough to tour?"). Sanity-check on a Zestimate. Spotting list-price outliers in a county's active inventory. Don't use for binding values.
Sources: Redfin Data Center (county median PPSF), NAHB hedonic studies (bed / bath effects). Methodology composed by HomeStats.