Los Angeles Room Addition Cost Calculator
Home Additions Calculator
Get accurate cost estimates for your home improvement project
Select Your Project Type(s)
Room Addition
Add new rooms, expand living space, or build a second story to your home
Bathroom Addition
Add a new bathroom, powder room, or luxury spa bathroom to your home
Master Suite Addition
Create a luxurious master bedroom with ensuite bathroom and walk-in closet
Project Details
Cost Estimate Breakdown
Note: These estimates include materials, labor, permits, and standard contractor overhead for Los Angeles County. Actual costs may vary based on site conditions, specific requirements, and contractor selection. We recommend getting 3-5 quotes from licensed contractors.
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Disclaimer: This calculator provides rough estimates for informational purposes only and does not constitute a binding quote or guarantee. Actual costs may vary significantly. Learn more..
Room Addition Costs in Los Angeles County
Room addition costs in Los Angeles County typically range from $280-$400 per square foot, making it one of the most cost-effective ways to add value to your home. Most homeowners invest between $80,000-$300,000 for complete addition projects, including:
- Home Additions: $150,000-$250,000 (500-800 sq ft expansions)
- Master Suite Additions: $120,000-$200,000 (bedroom, bathroom, closet)
- Bathroom Additions: $50,000-$100,000 (full bath with luxury finishes)
- Second Story Additions: $200,000-$400,000 (doubles living space)
Regional cost variations reflect local labor rates and permit requirements:
- Beverly Hills/West LA: $350-$400 per sq ft
- Hollywood Hills/Studio City: $320-$365 per sq ft
- Pasadena/Glendale: $300-$320 per sq ft
- San Fernando Valley: $280-$310 per sq ft
- East LA County: $275-$295 per sq ft
Popular Addition Types & ROI
Master Suite Additions generate the highest returns, adding $150,000-$250,000 in home equity while creating luxury living space. These additions typically include a spacious bedroom, walk-in closet, and spa-like ensuite bathroom.
Bathroom Additions solve space constraints while adding substantial value. Additional bathrooms are highly sought after in LA’s competitive housing market, especially full baths with modern amenities.
Kitchen Extensions accommodate open-concept living that LA buyers demand. Expanding kitchen space for islands, dining areas, or family rooms creates the entertaining spaces essential for California lifestyle.
Factors Affecting Addition Costs
- Permits & Inspections: $8,000-$15,000 (LA County has comprehensive requirements)
- Foundation Requirements: $12,000-$25,000 (varies by soil conditions)
- Utilities Extension: $5,000-$15,000 (electrical, plumbing, HVAC)
- Structural Engineering: $5,000-$12,000 (required for most additions)
- Finish Level: Economy (-15%), Standard, or Luxury (+35%)
Why Use Our Room Addition Calculator?
Our calculator incorporates LA County-specific factors including local permit fees, labor rates, and material costs. Get personalized estimates for your exact location, from luxury areas like Beverly Hills to value-conscious regions like the San Fernando Valley.
Ready to expand your home? Use our calculator above to discover how a room addition can transform your living space while building long-term equity in Los Angeles County’s dynamic real estate market.

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“Legal Disclaimer: This calculator provides rough cost estimates based on historical data and industry averages and does not constitute a binding quote, proposal, or contractual offer. Actual construction costs may vary significantly based on numerous factors including but not limited to: site-specific conditions, soil composition, utility accessibility, local permit requirements, material price fluctuations, labor availability, design complexity, building code compliance requirements, environmental conditions, inspection fees, unforeseen site complications, contractor selection, timeline constraints, and current market conditions. No warranty, express or implied, is made regarding the accuracy, completeness, or reliability of these estimates. Users should obtain professional quotes from licensed contractors and consult with qualified professionals before making any construction or financial decisions. This tool is provided for informational purposes only and should not be relied upon as a substitute for professional advice.“