An accessory dwelling unit (ADU) is one of the best ways to add space, rental income, or room for family on a Los Angeles property — but the first question every homeowner asks is, “what will it cost?” The honest answer is that it depends on the type of ADU, its size, your site conditions, and your finishes. Below is a realistic 2026 breakdown to help you plan. For an exact number on your property, request a free estimate from our team.

ADU Cost in Los Angeles by Type (2026)

As a general planning guide, ADUs in Los Angeles typically run from around $150,000 to over $400,000, and costs vary widely by type:

  • Garage conversion ADU — roughly $90,000–$245,000+. Usually the most affordable option because it reuses an existing structure. Basic conversions start lower; extensive structural upgrades push the top end.
  • Attached ADU — roughly $150,000–$325,000. Shares a wall with the main home; typically mid-range.
  • Detached new-construction ADU — roughly $200,000–$450,000+. The most flexible and the most expensive, since it’s built from the ground up. Larger or premium units can exceed $400,000.
  • Junior ADU (JADU) — roughly $50,000–$150,000. Converts up to 500 sq ft of existing interior space; often the most cost-effective path.

Cost Per Square Foot

In Los Angeles, ADU costs generally land between $250 and $600+ per square foot. Garage conversions often fall around $200–$450/sq ft, while detached new construction sits at the higher end. These are planning ranges — your actual number depends on the factors below.

What Drives ADU Cost

  • ADU type — conversion vs. ground-up construction is the biggest single factor
  • Size — more square footage means more cost, though cost-per-sq-ft can drop on larger units
  • Site conditions — grading, access, and soil can add cost
  • Utility connections — water, sewer, gas, and electrical hookups
  • Finishes — standard vs. premium materials and appliances
  • Permits and design — plan review and city fees

How to Get the Most Value

A garage conversion is usually the most budget-friendly way to add a legal unit, while a detached ADU offers the most flexibility and privacy. The right choice depends on your lot, your goals, and your budget. Because we handle ADUs and garage conversions with in-house design/build, we can help you weigh the trade-offs before you commit — and give you a clear written estimate.

Frequently Asked Questions

What is the cheapest type of ADU to build in Los Angeles?

A JADU (converting existing interior space) or a garage conversion is typically the most affordable, since both reuse existing structure rather than building from the ground up.

Why are detached ADUs more expensive?

Detached ADUs are built new from foundation to roof, including their own systems and finishes, so they cost more than converting an existing garage or interior space.

How do I get an accurate ADU cost for my property?

The only way to get a real number is an on-site assessment. We’ll look at your lot, goals, and conditions and provide a detailed written estimate.

Get a Free ADU Estimate

Thinking about an ADU or garage conversion in Los Angeles? Talk with a licensed, family-owned general contractor (CSLB #1081371). Call or text (323) 484-8458 or request your free estimate.