Free Instant Estimate

ADU Cost Calculator

Get an accurate estimate for your accessory dwelling unit in under 60 seconds. No email required.

1

Where is your property?

Location affects labor costs, permits, and material pricing

2

What type of ADU?

Different build types have different costs and timelines

3

How large should it be?

Size is the biggest factor in overall cost

600 sq ft
200 sq ft Studio 1 Bed 2 Bed 1,200 sq ft
4

What finish quality?

Choose your interior finish level

Step 1 of 4
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Understanding ADU Construction Costs

Building an accessory dwelling unit (ADU) is a significant investment that can transform your property and financial future. Our ADU cost calculator provides instant estimates based on real market data from across the United States.

What Affects ADU Costs?

Several factors influence the total cost of building an ADU:

  • Location: Labor costs, material prices, and permit fees vary significantly by state and city. California and Hawaii typically have the highest costs, while states in the Midwest and South tend to be more affordable.
  • ADU Type: Detached ADUs require new foundations and utilities, making them more expensive than attached additions or garage conversions.
  • Size: Larger ADUs cost more to build, though cost per square foot often decreases with size due to economies of scale.
  • Finish Quality: Premium materials and custom finishes can add 20-40% to base construction costs.

Average ADU Costs by State

ADU construction costs vary widely across the country:

  • California: $250-$450 per sq ft (highest in Bay Area, Los Angeles)
  • Washington & Oregon: $200-$350 per sq ft
  • Texas & Florida: $150-$275 per sq ft
  • Midwest States: $125-$225 per sq ft

Is an ADU Worth the Investment?

ADUs offer excellent return on investment through:

  • Rental Income: Generate $1,500-$3,500+ monthly depending on location and size
  • Property Value: ADUs typically increase home values by 20-30%
  • Flexibility: Use for family, guests, home office, or rental income
  • Tax Benefits: Potential depreciation deductions for rental properties

Frequently Asked Questions

How accurate is this ADU cost calculator?

Our calculator provides estimates based on current market data and typical project costs. Actual costs can vary by 15-25% based on site conditions, specific design requirements, and current material prices. For a precise quote, we recommend scheduling a free consultation.

What's included in the construction cost estimate?

Our estimate includes foundation, framing, roofing, siding, windows, doors, electrical, plumbing, HVAC, insulation, drywall, flooring, kitchen appliances, bathroom fixtures, and standard finishes. Site preparation and utility connections are shown separately.

How long does it take to build an ADU?

Typical timelines are: Garage conversions (3-4 months), attached ADUs (4-6 months), and detached ADUs (6-9 months). Permitting can add 2-6 months depending on your jurisdiction.

Do I need permits to build an ADU?

Yes, ADUs require building permits in all states. Many jurisdictions have streamlined ADU permitting processes. Our team handles all permit applications as part of our full-service packages.

Can I finance my ADU construction?

Yes, there are several financing options including home equity loans, HELOCs, construction loans, and some specialized ADU financing programs. Many homeowners see positive cash flow from day one when renting their ADU.

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