FREE ESTIMATION TOOL
ADU Cost Calculator
Get an instant estimate for your ADU project in the Bay Area. Select your city, ADU type, size, and finish level.
Contact UsEstimate Your ADU Construction Cost
Use our free calculator to get a rough estimate of what your ADU project might cost in the Bay Area. Adjust the options below and click Calculate to see your personalized estimate.
500 sq ft
Estimated Total Cost Range
Cost Breakdown
These estimates are for planning purposes only. Actual costs vary based on site conditions, design complexity, and market conditions. Contact us for a detailed quote.
ADU Cost Calculator FAQ
Common questions about ADU costs in the Bay Area.
This calculator provides rough estimates based on average Bay Area construction costs. Actual costs depend on site conditions, soil type, permit requirements, and design complexity. For a precise quote, contact 9Builders for a free consultation.
The estimate includes design, permits, site preparation, construction, finishing, and a 10% contingency. It does not include furniture, landscaping, or utility connection fees which vary by city.
Bay Area construction costs are driven by high labor rates, strict building codes, lengthy permit timelines, and elevated material costs. Skilled tradespeople in Santa Clara County command some of the highest wages in the nation.
Garage conversions are typically the most affordable option since the existing structure provides the foundation and framing. Junior ADUs (JADUs) are also cost-effective as they convert existing space within the main home.
Most ADU projects take 8 to 14 months from design to completion. The permit approval process alone can take 2 to 6 months depending on your city. Construction typically takes 4 to 6 months once permits are approved.
Yes. 9Builders is a full-service ADU contractor serving the entire Bay Area. We handle design, permits, construction, and inspection. Contact us for a free consultation to discuss your project.