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ADU Cost Calculator

Detached ADU: Detached ADU: Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.50-$450/sqft. Attached ADU: Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.5K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.50-$450/sqft. Attached ADU: Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.5K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.50-$450/sqft. Attached ADU: Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.5K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.50-$450/sqft. Attached ADU: Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.50-$450/sqft. Attached ADU: Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.00-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.5K-$40K. This calculator sizes. ADU economics often depend heavily on local jurisdiction: California's SB9/SB8 laws have slashed permit timelines and fees for qualified projects. Pre-approved plan programs in many cities cut design cost 40-60%. Utility tap fees are the single largest wild card and should be researched with local agencies before committing to a budget — often Detached ADU: $150-$450/sqft. Attached ADU: $100-$300/sqft. Garage conversion ADU: $60-$200/sqft. Permits, utilities, landscaping adds $15K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.5K-$40K. This calculator sizes.0K-$25K of total cost lives here alone.

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Total ADU cost

$208,000

Construction cost

$180,000

How the math works

600 sqft detached ADU at $300/sqft = $180K + $8K permits + $15K utilities + $5K landscaping = $208K all-in.

CA has streamlined ADU approvals (SB9, SB8). Many other states and cities have followed. Check local ADU program before starting design — can save $20K-$50K via pre-approved plans or fee waivers.

How to Use

  1. Pick ADU type and sqft.
  2. Add fees, utilities, landscaping.
  3. See total cost.

Frequently Asked Questions

Which ADU type cheapest?

Garage conversion: lowest cost, fastest (2-4 months). Existing structure = less foundation/framing. Attached: mid. Detached new-build: most expensive but highest rental value and flexibility.

Permit and utility fees?

Permits $2K-$10K. Utility connections: $5K-$25K (sewer/water tap fees). Impact fees $2K-$15K in some CA cities. Add $15K-$50K total in fees before you buy lumber.

Financing?

ADU construction loan, HELOC, cash-out refi. Some states have ADU-specific programs (CA has CalHFA ADU Grant Program up to $40K). Start with the state and city resource office.

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