ADU Cost Calculator

Based on your inputs and real ADU projects in California
Plot
ADU
Site
Cost
Results
Basic information about the plot
Estimate your ADU project costs based on key factors
City / Region:
*Some cities have higher permitting and construction overhead, which can affect total project cost and timeline.
Plot Type
*Lot shape and layout influence construction logistics and cost efficiency.
Property Access:
Construction Access:
*Limited construction access may increase labor time and equipment costs.

ADU Cost Calculator

Based on your inputs and real ADU projects in California
Plot
ADU
Site
Cost
Results
ADU Type and Size
This selection affects construction scope and cost only. ADU type eligibility depends on zoning and site conditions.
ADU Type
*Standalone ADUs are typically more expensive than conversions due to new foundations, utilities, and structural work.
Square Footage: 340 sq ft
100 sq ft
1, 200 sq ft
Larger ADUs require more materials, labor, and engineering—this increases the total cost but often lowers the price per square foot.

ADU Cost Calculator

Based on your inputs and real ADU projects in California
Plot
ADU
Site
Cost
Results
Site Cost Factors
Factors that influence cost
Finish level:
Slope of the plot:
Balanced quality and price (chosen by most owners)
*Sloping plots complicate the foundation and drainage — on average, this adds +25% to the cost.
Utility Connection Distance:
*Longer utility runs require trenching and coordination, increasing construction cost.
These factors affect construction cost only and do not confirm site feasibility.

Estimated ADU Construction Cost

Based on typical project assumptions. Final cost depends on site verification and design.
Plot
ADU
Site
Cost
Results
Conservative
Standard conditions, minimal site complexity
Cost range:
$xxx,xxx – $xxx,xxx
Cost per sq.ft:
$xxx,xxx
Most Likely
Typical ADU project based on similar builds
Cost range:
$xxx,xxx
Cost per sq.ft:
$xxx,xxx
Higher Complexity
Slope, utilities relocation, premium finishes
Cost range:
$xxx,xxx
Cost per sq.ft:
$xxx,xxx – $xxx,xxx
What this estimate assumes
$xxx,xxx – $xxx,xxx
*Exact numbers are shown after unlocking your results
Conservative
Most Likely
Higher Complexity
Effective cost per sq.ft
~ $XXX / sq.ft
Estimated timeline:
~ $XXX / sq.ft
Includes design, permits, and construction
Based on 120+ ADU projects in California
Updated quarterly using real permit data
Used by homeowners in LA, SD, SF

Your Full ADU Cost Estimate

Here’s a detailed cost breakdown based on your inputs, including realistic ranges, cost per sq. ft, and an estimated project timeline.
Conservative
Standard conditions, minimal site complexity
Cost range:
$240,000 – $360,000
Cost per sq.ft:
$240,000 – $360,000
What drives your cost
What this estimate does NOT include
$240,000 – $360,000
*Exact numbers are shown after unlocking your results
Conservative
Most Likely
Higher Complexity
Effective cost per sq.ft
~ $700 / sq.ft
Estimated timeline:
9–12 months
Includes design, permits, and construction
Based on 120+ ADU projects in California
Updated quarterly using real permit data
Used by homeowners in LA, SD, SF

Your Full ADU Cost Estimate

Here’s a detailed cost breakdown based on your inputs, including realistic ranges, cost per sq. ft, and an estimated project timeline.
Most Likely
Typical ADU project based on similar builds
Cost range:
$240,000 – $360,000
Cost per sq.ft:
$240,000 – $360,000
$240,000 – $360,000
*Exact numbers are shown after unlocking your results
Conservative
Most Likely
Higher Complexity
Effective cost per sq.ft
~ $700 / sq.ft
Estimated timeline:
9–12 months
Includes design, permits, and construction
Based on 120+ ADU projects in California
Updated quarterly using real permit data
Used by homeowners in LA, SD, SF

Your Full ADU Cost Estimate

Here’s a detailed cost breakdown based on your inputs, including realistic ranges, cost per sq. ft, and an estimated project timeline.
Higher Complexity
Slope, utilities relocation, premium finishes
Cost range:
$240,000 – $360,000
Cost per sq.ft:
$240,000 – $360,000
$240,000 – $360,000
*Exact numbers are shown after unlocking your results
Conservative
Most Likely
Higher Complexity
Effective cost per sq.ft
~ $700 / sq.ft
Estimated timeline:
9–12 months
Includes design, permits, and construction
Based on 120+ ADU projects in California
Updated quarterly using real permit data
Used by homeowners in LA, SD, SF

Project Details

These details help us better understand your goals and priorities
When would you like to start your ADU project?
What budget range feels comfortable for you?
Do you want us to verify your site assumptions?
*Site verification confirms whether the cost assumptions used in this estimate match real conditions.
This calculator provides cost estimates only and does not determine zoning feasibility or permit approval.
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