Plan first
Planning tools
Three free tools, each one a range, not a quote. Start with the cost, see what it could rent for, and compare the ways to pay.
ADU cost planner
A planning range for your lot, with the line items behind it.
$82,560to$428,632
All ADU types at a plain spec, from the cost calculator today.
ADU rent and return planner
What an ADU could rent for, and how the numbers come together over time.
9.4to12.7 years
Simple payback for a detached ADU at HUD's typical two-bedroom rent (HUD FY2027 metro rent), from the return planner today.
Financing guide and loan calculator
Cash, a HELOC, a home equity loan, a refinance or a construction loan, side by side.
7.03% 30-year average, 2026-09-24
Published average rates, dated. Not an offer of credit.
San Diego ADU permit checklist
One page of what to check before you design an ADU in the City of San Diego.
A PDF you can print.
