The number that matters
comes before the bid.
Most homeowners talk to contractors before they understand what ADUs cost in their market. That information asymmetry is expensive. This site exists to close it — with real regional data, not national averages that mislead 80% of the people who read them.
Browse All 50 State Guides →Regional, not national
Construction costs in Memphis and Manhattan differ by 3×. Our data is built from local labor rates, permit records, and regional multipliers — not averaged into meaninglessness.
Type-specific pricing
A garage conversion costs half what a detached new build costs. We break down all six ADU types with separate cost models — because the type changes everything.
Permits explained, honestly
We cover what your city actually requires, how long it takes, what it costs, and what trips people up. Not a generic checklist — specific to your market.
ROI you can model
Local rental rates, payback periods, and property value impact by city. The data you need to make the investment decision before you commit to anything.