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Planning an ADU can feel overwhelming, but the right tools and guidance make it simple. Our goal is to empower homeowners with upfront pricing, transparent services, and clear expectations — so you can move forward confidently with your ADU project.
Looking to build an ADU in California? You’re in the right place. Our ADU cost calculator — also known as our Accessory Dwelling Unit Calculator — gives you a fast, transparent ADU quote based on your project needs — in under 60 seconds.
Whether you’re planning a backyard ADU, garage conversion, or a detached unit, our smart estimator helps you understand your ADU pricing upfront. No guesswork, no hidden fees.
We’ve designed this tool to reflect real-world construction data, design fees, and the full ADU permit price — so your ADU estimate is accurate and ready to go. It’s ideal for anyone wanting to understand the true cost of an accessory dwelling unit before starting their project
At PAS Architects, we don’t just provide an ADU quote — we handle the full process from code review to permit approval. Every ADU cost calculator estimate includes the following services:
Existing Conditions & Code Review
On-site measurement and existing-conditions documentation
Code compliance check and permit strategy tailored to your city
Design & Documentation
Schematic design and floor plan development
Detailed exterior and interior elevations with full construction drawings
Coordination & Management
Coordination with consultants (Structural, MEP, Title 24, Soils)
City submittals, plan-check responses, and ADU permit price breakdown
Full project management until permit approval
As an experienced ADU architect in California, PAS Architects brings local zoning knowledge and hands-on project support from design to permits. Whether you’re in Cerritos, Long Beach, or the hills of Altadena — we help you plan smart and build with confidence.
Try the ADU Cost Calculator tool now — it’s free, fast, and requires no sign-up. You’ll get a detailed ADU fee estimate tailored to your location, goals, and budget.
Ready to explore your ADU options? Use our calculator and get your quote today.
Thinking about building an ADU in Los Angeles County? You’re not alone — ADUs are one of the most popular ways to create flexible, affordable housing. Whether it’s a garage conversion, backyard cottage, or detached in-law suite, it’s important to understand local zoning and permitting rules. For the most up-to-date requirements, visit the Los Angeles County Accessory Dwelling Unit Planning Guide.
| Feature | Description |
|---|---|
| How much does it cost to build an ADU in California? | Costs vary by type and size, but most ADUs range from $100,000 to $350,000. Use our instant calculator to get a real estimate based on your property and needs. |
| How much does an 800 square foot ADU cost? | An 800 sq ft ADU typically costs between $160,000 and $280,000 in California, depending on site conditions, materials, and design. Use our ADU cost calculator to get a tailored estimate in seconds. |
| How to calculate cost for ADU? | To calculate ADU pricing, factor in construction, design, city fees, and site conditions. Our free ADU quote tool breaks this down instantly for your specific location and scope. |
| What types of ADUs can I build? | We offer detached ADUs, attached ADUs, garage conversions, and Junior ADUs (JADUs). Whether you’re maximizing your lot or building a simple guest unit, we have a plan for you. |
| How much are your architectural fees for ADUs? | Our ADU architecture packages start as low as $5,950 for garage conversions. We also offer affordable plot plans for LA County’s pre-approved ADUs and full-service design for custom builds. |
| What is the cheapest way to build an ADU? | The most affordable option is usually a garage conversion. It uses existing structure and utilities, cutting costs. Our garage conversion plans start at just $5,950. |
| What is the most expensive part of building an ADU? | Construction labor and utility connections are usually the highest costs, especially for sloped lots, limited access, or upgraded electrical/sewer needs. |
| Can I really get an ADU quote instantly? | Yes — our smart estimator gives you a custom quote in under a minute. No signup required. It includes permit costs, architectural fees, and a base construction estimate. |
| Do you serve my area? | PAS Architects proudly serves Cerritos, Long Beach, Pacific Palisades, Altadena, and surrounding areas throughout Southern California. |
