Short answer
Bay Area cost per square foot is a blunt tool. It works for early screening, then you need drawings, assumptions, and line items.
Bay Area variables
What changes the budget here.
Small projects can cost more per foot
Kitchens, baths, and ADUs have dense plumbing, electrical, cabinets, fixtures, and inspection requirements.
Large projects hide site costs
Custom homes and additions can bury major site work, structural, and utility costs outside the simple per-foot number.
Use a range, then refine
The first range should tell you whether the idea is plausible. The second estimate should price actual scope.
Cost table
Directional planning ranges.
| Project | Planning range | Notes |
|---|---|---|
| Garage conversion | $170-$340+/sq ft | Existing garage quality decides the spread. |
| ADU | $250-$600+/sq ft | Small footprint plus full-house systems. |
| Addition | $400-$850+/sq ft | Tie-ins, structure, kitchens, baths, and second story complexity. |
| Custom home | $500-$900+/sq ft | Site and design intensity are decisive. |
Local estimate
Run the calculator with Bay Area pressure included.
Live calculator
Bay Area planning range
Value first. No email wall, no fake exact quote.
Want a human to sanity-check the range?
Optional. The estimate already did its job. Send it only if you want a Bay Area planning review.
FAQ
Bay Area answers.
Is this a contractor bid?
No. It is a planning estimate that helps you understand the likely budget range before drawings, engineering, city review, and contractor pricing.
Why is the range wide?
Early construction budgets should be ranges because site conditions, structural scope, utility work, finishes, permits, and contractor availability can move the number fast.
Do I need to enter contact information?
No. The estimate appears first. Contact information is only for saving the estimate or asking for a local review.