Short answer
A custom home estimate is really a site, design, engineering, finish, and risk estimate. Square footage is only the starting point.
Cost drivers
What moves the number.
Site work can dominate
Slope, access, soils, drainage, utility connections, and retaining walls can move the budget before the house starts.
Design decisions have compounding cost
Structure, glazing, spans, ceiling heights, exterior systems, and custom details affect every trade.
Budget before architecture
A beautiful design that ignores budget is not ambitious. It is expensive fan fiction.
Planning ranges
Use ranges until scope is real.
| Line item | Planning range | Why it moves |
|---|---|---|
| Semi-custom | $280-$500+/sq ft | Less bespoke structure and finish system. |
| Custom | $500-$900+/sq ft | High design, difficult site, premium materials, and Bay Area labor. |
| Soft costs | 10%-22%+ | Architecture, engineering, surveys, permits, utilities, and consultants. |
FAQ
Fast 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.