ADU Cost by Size — Interactive Calculator
Drag the slider to see 2026 all-in accessory dwelling unit cost ranges (hard + soft + permits + utilities) for 16 US metros. Pick a city, pick a size, copy a shareable link.
Cost Breakdown (Mid-Range)
| Category | Amount | Share of Mid Total |
|---|---|---|
| Hard construction (labor + materials) | $330,000 | 83% |
| Soft costs (design, engineering, PM) | $39,600 | 10% |
| Permit and impact fees | $18,000 | 5% |
| Utility hookups | $12,000 | 3% |
| Mid-range total | $399,600 | 100% |
Last updated April 2026.
How We Calculate This
These are 2026 all-in market estimates. Hard costs scale linearly with square footage using a low/mid/high per-sq-ft band calibrated to recent build data in each metro. Soft costs (design, engineering, project management) are applied at ~12% of hard costs. Permit and utility hookup fees are set to local base amounts and lightly adjusted for size. For an itemized estimate tied to your lot, finish level, and specific city jurisdiction, use our Cost Estimator.
All 16 Metros at 600 sq ft
| Metro | Low | Mid | High | Page |
|---|---|---|---|---|
| San Diego, CA | $314,160 | $399,600 | $530,040 | View 600 sq ft → |
| La Jolla, CA | $368,680 | $470,800 | $632,920 | View 600 sq ft → |
| Los Angeles, CA | $293,380 | $377,800 | $507,220 | View 600 sq ft → |
| Portland, OR | $238,860 | $306,600 | $404,340 | View 600 sq ft → |
| Denver, CO | $228,092 | $295,520 | $392,948 | View 600 sq ft → |
| Bay Area, CA | $354,700 | $457,000 | $619,300 | View 600 sq ft → |
| San Jose, CA | $353,000 | $455,000 | $602,000 | View 600 sq ft → |
| Oakland, CA | $335,620 | $437,200 | $583,780 | View 600 sq ft → |
| Seattle, WA | $295,930 | $380,800 | $510,670 | View 600 sq ft → |
| Sacramento, CA | $250,478 | $318,680 | $422,882 | View 600 sq ft → |
| Austin, TX | $220,630 | $287,800 | $384,970 | View 600 sq ft → |
| Phoenix, AZ | $201,363 | $261,780 | $349,197 | View 600 sq ft → |
| Scottsdale, AZ | $233,548 | $297,880 | $401,212 | View 600 sq ft → |
| Raleigh, NC | $189,439 | $246,340 | $330,241 | View 600 sq ft → |
| Charlotte, NC | $186,133 | $242,980 | $326,827 | View 600 sq ft → |
| Dallas, TX | $208,825 | $269,500 | $363,175 | View 600 sq ft → |
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Frequently Asked Questions
How accurate are these ADU cost estimates?
These are 2026 market estimates calibrated to recent builds in each metro. They are excellent for budgeting and feasibility, but not a substitute for a contractor bid. Actual cost varies with lot conditions, finish level, and specific jurisdiction.
Why does the cost per sq ft drop at larger sizes?
Permit fees and utility hookups are mostly fixed — they cost roughly the same whether you build 400 or 1,200 sq ft. Spreading those fixed costs over more square footage lowers the effective cost per sq ft.
What is included in the total cost?
Hard construction (labor and materials), soft costs (design, engineering, project management), permit and impact fees, and utility hookups. It does not include land, demolition, or lot-specific work like grading or retaining walls.
Can I finance the full build amount?
Usually yes. HELOC, construction-to-permanent loans, cash-out refinance, RenoFi, and DSCR (for rental ADUs) are all common. Use the ADU Loan Calculator to compare monthly payment and break-even rent.
How do I share a specific result?
Pick a city and size, then click Copy Deep Link. The URL points to a dedicated page for that city and size bucket with its own FAQ and breakdown.
Do these costs change over time?
Yes. We recalibrate the model quarterly based on local permit fee schedules, BLS labor rates, and recent builder bids in each metro. The last update was April 2026.
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