1. What kind of ADU are you thinking about?
Pick the project type closest to your plan.
2. How big?
Garage conversions typically run 400–600 sq ft.
3. What finish level?
Standard is clean and rental-ready. Upgraded adds nicer fixtures and finishes. Premium is top-shelf everything.
Garage Conversion · 500 sq ft · Upgraded finishes
Ballpark only — every lot, soil condition, and city fee schedule is different. This estimate is a starting point for planning, not a bid. Call for a free consultation and a fixed written quote.
How This ADU Cost Estimator Works
Pick your ADU type, size, and finish level, and the estimator calculates a ballpark range from real California project costs. The math is simple: every ADU type has a typical cost band, your size places you within that band, and your finish level adjusts it up or down. The range shown is ±10% around the midpoint, rounded to the nearest $5,000 — wide enough to be honest, tight enough to plan with.
What Moves Your ADU Price Up or Down
Three things move the number most. Site conditions — hillside lots, tight access, and poor soils add cost before a single wall goes up. Utility work — sewer, water, and electrical runs plus panel upgrades vary wildly lot to lot. Finishes — the gap between clean-and-rental-ready and top-shelf everything can swing a project 20% or more. City permit and impact fees differ by municipality too, which is why no online tool can replace a site-specific quote.
Get Your Fixed Written Quote
ADU Cities designs, permits, and builds ADUs across California — garage conversions, attached units, and detached backyard homes, all handled in-house by our own crews. Call 562.810.1965 for a free consultation and a fixed written quote for your property. Licensed California contractor, CSLB #1138550.
