Real numbers, not contractor optimism
What will your ADU actually cost?
Pick a city, an ADU type, a size, and a finish tier. We pull your city's real permit fee, multiply by current per-sqft build costs, layer on soft costs and contingency, and show you a defensible range.
Based on Detached new construction · 800 sqft · Standard finish in Santa Monica. Property uplift assumes a single-family lot baseline of $1M.
Line-by-line breakdown
- Build & finishes (360–$460/sqft × 800)$288k–$368k
- City permit & plan check$8.2k
- Soft costs (design, survey, soils — 5–8% of build)$14k–$29k
- Utility connections$8k–$14k
- Contingency (10%)$31k–$41k
Drop your email to see every line item.
Soft costs, contingency math, utility hookups. No spam. Omar reads every email.
How this is calculated.
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01
Build cost band
Per-sqft cost range for your ADU type (detached / attached / garage conversion) from our 2026 LA-area cost survey, multiplied by the finish tier (basic 0.85×, standard 1.00×, luxe 1.30–1.35×).
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02
City permit fee
Your selected city's typical permit + plan-check fee, pulled directly from the city's published fee schedule and verified May 2026.
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03
Soft costs & utilities
Design, survey, soils, structural review: 5–8% of build. Utility connections: $8k–$14k. Both are conservative defaults.
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04
Contingency
10% of the subtotal. Don't skip this — change orders, site conditions, and price drift eat through it predictably.
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05
Property value uplift
Typically 25–35% of lot value in LA-area markets, based on Fannie Mae appraisal guidance. We show against a $1M baseline.
Now find a builder who delivers in your band.
We hand-pick three local builders who've actually permitted and finished ADUs at your size and finish tier.