Understanding the Сost to
Build an ADU in California
Thinking about adding more space or making a smart investment in your property?Figuring out how much it’ll cost to build an ADU (Accessory Dwelling Unit) is a great place to start. Maybe you’re a homeowner dreaming of a backyard unit for family or extra income, or maybe you’re an investor looking to boost property value. Either way, understanding what goes into ADU cost in Los Angeles or anywhere else in California can help you plan with confidence.
We at ADU Pro like to keep it simple. We provide clarity around design, permitting, and - most importantly - budgeting. Let’s break down what you need to know about the cost to build an ADU house in today's market.
Get in touchWe at ADU Pro like to keep it simple. We provide clarity around design, permitting, and - most importantly - budgeting. Let’s break down what you need to know about the cost to build an ADU house in today's market.
Factors Influencing
ADU Costs
No two ADUs are alike, and that's why prices vary. Still, there are common factors that influence ADU cost California:
Structure type
Detached, attached, or converted garage.
Size and configuration
Square footage, number of bedrooms, bathrooms, and degree of design sophistication.
Construction method
Ground-up construction vs. garage ADU conversion cost.
Site conditions
Sloped land, utility connections, and accessibility.
Local fees and permits
These vary by city and county across California.
Finish level
Standard vs. high-end materials and appliances.
For example, a standard garage ADU conversion cost is generally lower than a brand-new detached unit, primarily because the structural foundation already exists.
ADU Cost Calculator
The Costs of Building an ADU
Building a mini home ADU is more affordable than buying a new property but still requires planning. Here’s what to expect:
Garage Conversion ADU
$60,000 – $150,000
Attached or Junior ADU
$100,000 – $200,000
Detached ADU (Tiny Home ADU)
$150,000 – $400,000
Size, materials, utilities, and local permitting fees all factor into cost.
Get an accurate estimate with our "ADU Cost Calculator" tool.
Get My Cost EstimateGet an accurate estimate with our "ADU Cost Calculator" tool.
Why Invest in
an ADU?
Building an ADU isn’t just about creating extra space - it’s a strategic investment. That's why increasing numbers of Californians are opting for it:
Rental income
With a well-designed ADU, you can earn $2,000–$3,500 per month depending on unit size and location.
Family housing
Increases 20–30% on average on total real estate value, according to California Housing Partnership.
Sustainability
Smaller living areas use fewer resources and align with modern, eco-friendly lifestyles.
When comparing options, recognizing how much it will cost to build an ADU house versus buying a larger property tends to highlight the value and flexibility of increasing on-site living space.
Making Sense of ADU Costs: Budget Tips
At ADU Pro, we help you identify where your investment will have the most impact. Here are a few tips to manage your ADU cost California efficiently:
Plan ahead
The clearer your vision, the fewer surprises down the road.
Optimize the footprint
Maximize utility in a compact space to reduce per-square-foot cost.
Pre-approved schemes
Most municipalities have pre-approved schemes that reduce design and permitting costs.
Work with experienced teams
Seasoned teams with ADU experience will guide you around possible pitfalls and keep your project on track.
FAQ
Questions to Consider Before You Get Started
What is my total expense, including soft expenses (permits, design) and hard expenses (construction)?
Your total expense includes both soft costs, such as permits, design, and engineering fees, and hard costs, which cover the actual construction work, materials, and labor. Add both together to get the full project cost.
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Your total expense includes both soft costs, such as permits, design, and engineering fees, and hard costs, which cover the actual construction work, materials, and labor. Add both together to get the full project cost.
Label
Your total expense includes both soft costs, such as permits, design, and engineering fees, and hard costs, which cover the actual construction work, materials, and labor. Add both together to get the full project cost.
Label
Your total expense includes both soft costs, such as permits, design, and engineering fees, and hard costs, which cover the actual construction work, materials, and labor. Add both together to get the full project cost.
Label
Your total expense includes both soft costs, such as permits, design, and engineering fees, and hard costs, which cover the actual construction work, materials, and labor. Add both together to get the full project cost.
Get Started with ADUSCALE Today
Ready to make the most of your property? Whether you're thinking about a small home ADU, a tiny home, or a fully detached ADU, we’re here to help.