How our value estimates work
Every building page shows our estimated market value next to the county's own numbers. This page explains what feeds that estimate, how the model works, and exactly how accurate it measured on recent sales. It is an estimate, not an appraisal, and we publish the error numbers because you deserve to know how much to trust it.
What feeds it
Public records only: county assessor rolls, recorded real property sales where available, county GIS parcel data, and each county's own building or use records. No private data feeds the model, and each county uses only its own approved facts.
How the model works
The app routes every property to its county's active model. King County uses the richer hedonic model: sale-to-county-value ratios adjusted for time, land share, building age, size, lot, scale, type, and city, blended with nearby verified sold buildings, component land/improvement checks, and a price-per-square-foot cross-check. Maricopa uses its own lower-confidence assessed-ratio model based on full cash value, city, and property type. No county borrows another county's comps. Estimates refresh with each county data release.
The range, honestly
The range we show is a measured error, not a guess: it comes from the actual spread between our predictions and real later sale prices. About half of recent verified sales landed inside their range. When a segment has too few sales to measure, we widen the range or hold the estimate entirely.
Income view
For parcels with real building square footage and enough sale support in their segment, we also show a separate income view. It models annual rent per square foot, vacancy, operating costs, annual NOI, and a going-in cap rate, then divides NOI by that cap rate. This income value is a cross-check beside the MakeMe Estimate; v1 does not blend the two into one headline. If rent support, cap-rate support, or real building square footage is missing, the income view does not render.
Income view tested on 489 recent verified sales the income model had never seen. Median error 25.6%; 40% landed within 20%; 50% landed inside the shown income range.
| Segment | Sales tested | Median error | Within 10% | Within 20% | Inside range |
|---|---|---|---|---|---|
| multifamily | 218 | 20.7% | 20% | 48% | 50% |
| retail | 101 | 33.5% | 17% | 31% | 51% |
| industrial | 93 | 26.3% | 17% | 39% | 51% |
| office | 77 | 38.7% | 22% | 30% | 51% |
Measured accuracy (through 2026-06-01)
King County, WA (Seattle-Bellevue metro): tested on the most recent 12 months of verified sales the model had never seen (562 sales). Median error 15.7%; 33% of estimates landed within 10% of the real price and 62% within 20%; 51% of sales fell inside the shown range. The segment table below is King County.
| Segment | Sales tested | Median error | Within 10% | Within 20% | Inside range |
|---|---|---|---|---|---|
| multifamily | 218 | 11.7% | 43% | 76% | 50% |
| retail | 101 | 21.2% | 19% | 48% | 51% |
| industrial | 93 | 21.8% | 29% | 48% | 46% |
| office | 77 | 15.1% | 35% | 66% | 51% |
| other commercial | 73 | 19.7% | 25% | 53% | 51% |
Maricopa County, AZ (Phoenix metro): the assessed-ratio model was holdout-tested on 3,891 verified arm's-length sales recorded since 2022-01. Median error 18.7%; 53% of estimates landed within 20% of the real price. The served range spans 0.80x to 1.19x of the midpoint, measured so about half of real sales land inside it (through 2026-06-29).
Off-market commercial estimates run wider than home-value tools: there are fewer sales, and public records do not contain rent rolls or in-place NOI. We publish our numbers anyway, per county, and they improve with every county refresh and every recorded sale.
What this is not
Our estimate is not an appraisal and no appraiser is involved; where a county value appears it carries the county's own label. Everything on this site comes from public records and our models, provided as is, without warranty. It is not investment, legal, or tax advice. It is a starting point for a conversation between principals. County values are per the owning county assessor.
More about the platform: about makeme1031.