The honest ranges
Most of the ADUs we design and build range from $300,000 to $1.5 million. Junior ADUs, created within the footprint of the existing home, can start around $225,000. These are wide ranges on purpose: an ADU is a complete small home, and its cost moves with the same forces as any home, including size, site, utilities, and finishes.
Every figure on this page is a range, not a quote. Each project carries its own site conditions, scope, and finishes, and the honest number for yours comes from a conversation, not a webpage.
What drives ADU cost
Size and type come first. A junior ADU inside the existing house involves far less new structure than a detached two-bedroom unit. Site conditions come second: utility connections, grading, access for equipment, and hillside work can each move the number meaningfully. Finishes come third, and they are where you hold the most control, from clean and durable to fully bespoke.
Garage conversions often land at the lower end of the range because the structure, slab, and roof already exist. Detached units with full kitchens, laundry, and custom finishes occupy the upper end.
Why design-build protects your budget
The most expensive words in construction are we did not plan for that. In our design-build model, the builder helps create the plans, so constructability and cost are checked at the drawing stage rather than discovered on site. We talk candidly about budget at the first consultation, design to the number we agree on, and tell you before anything is drawn if a wish and a budget do not match.
Related: Guide to building an ADU in Los Angeles, ADU design and construction.
Common questions
What is the cheapest way to add an ADU?
Usually a junior ADU or a garage conversion, because both work within structure that already exists. Junior ADUs in our experience can start around $225,000, with the final number depending on the specifics of the home.
Does the $300,000 to $1.5 million range include design and permits?
Our ranges reflect complete design-build projects. At your consultation we break down exactly what your project includes so there is nothing vague about the number you approve.
Can you design an ADU to a specific budget?
Yes. That is the core of how we work: we agree on a realistic number first, then design the unit to honor it.