Methodology & data sources

Where the numbers come from

Sales tax rates: imported from state revenue departments (California's CDTFA rate files quarterly; other states per their schedules). Rates are attributed to the issuing agency and are not certified — always displayed with the resolved jurisdiction so you can spot boundary mismatches.

Doc fee caps: statute-verified where cited (e.g., CVC §11713.1, ORS 822.043(4)); rows still under citation review are marked “verifying” until confirmed. CPI-indexed caps are re-reviewed every January.

Doc fee benchmarks (uncapped states): seeded from published industry surveys, then replaced by medians computed nightly from this site's own buyer reports once a state has 5+ reports.

Registration formulas: encoded from each state DMV's published fee schedule, with statute citations where available. Estimates are labeled — exact registration requires inputs (weight, county, plate status) that don't change your negotiation.

Vehicle data: VIN decodes via the federal NHTSA vPIC database, cached permanently.

How verification works

Every submission requires an email-verified account and passes moderation before publishing. Unverified reports are excluded from headline averages. Attested reports carry a sworn-accuracy attestation. Document-verified reports (coming soon) have paperwork reviewed by a moderator — documents are stored outside the web root, never displayed, and deleted after review.

Aggregate statistics display only at n ≥ 3 reports; below that we show individual reports only. Prices deviating more than 40% from the model median are flagged for human review before publishing.

What we compute vs. what we show

Submitted deals exclude taxes by design — tax depends on the buyer's ZIP, not the deal, so excluding it keeps deals comparable across jurisdictions. The calculator adds your jurisdiction's tax back using the rules engine.