ADU vs JADU: Size, Cost, and Rules Compared

You have a spare bedroom, an attached garage and a backyard, and you want rental income or a place for your mother. Then you hit a fork nobody explained: should you build an ADU or a JADU? The ADU vs JADU decision is one of the biggest choices in California housing, because the two are legally different, with different size caps, costs, kitchens and rules about whether you can move away and rent everything out.

Choose wrong and you can lock yourself into a deed restriction you did not want, or spend $250,000 when $70,000 would have done the job. Here is the honest comparison Los Angeles homeowners need before calling anyone.

What ADU vs JADU Means for Los Angeles Homeowners

A JADU, or junior accessory dwelling unit, is a small home carved out of space that already exists inside your house or attached garage. It cannot be new detached construction. An ADU is a full second home, detached in the yard, attached as an addition or converted from a garage.

That structural difference drives everything else. In Los Angeles, where lots are tight and older homes often have an unused bedroom or attached garage, a JADU is frequently the cheapest permitted path to a legal rental. Learn more about each option in our guide to types of ADUs.

ADU vs JADU Rules: Size, Kitchen, Bathroom and Occupancy

For the full list of local rules, see our guide to ADU requirements in Los Angeles.

ADU vs JADU Cost and Income

Here are typical Los Angeles ranges for 2026:

• JADU from a bedroom or interior space: roughly $50,000 to $90,000.
• JADU from an attached garage with a private bathroom: often $60,000 to $120,000.
• Garage conversion to a full ADU: often $100,000 to $180,000.
• Detached ADU: roughly $200,000 to $320,000 or more.

The income side matters just as much. A JADU commonly rents for about $1,200 to $2,000 a month, depending on whether the bathroom is private. A full ADU often rents for about $1,800 to $4,500. JADUs also skip impact fees, while ADUs only skip them under 750 square feet. A JADU is cheaper and faster to finish. An ADU costs more but earns more. See our guides to the cost to build an ADU in Los Angeles and ADU rental income.

ADU vs JADU for Resale Value

If you may sell in the next few years, think about buyers too. An ADU is a larger, fully independent home with no occupancy limits, so it usually adds more resale value and appeals to more buyers, including investors. A JADU still adds value and flexible space, but its size cap and possible deed restriction make it a smaller selling point. Either way, a fully permitted unit always appraises better than an unpermitted one.

ADU vs JADU Mistakes That Cost LA Homeowners

• Going over 500 square feet: a JADU designed at 520 square feet is no longer a JADU, which changes fees and permit rules.
• Installing a full range in a JADU: inspectors know the difference between an efficiency kitchen and a full kitchen.
• Sharing the bathroom to save money: then finding the owner-occupancy rule stops you from moving out and renting both units.
• Ignoring parking rules: converting an attached garage can raise parking questions in some cities, so confirm before you design.
• Treating a JADU as a small ADU: they are legally separate categories with different rules.

A Contractor's Perspective on ADU vs JADU

After many Los Angeles projects, here is how we help homeowners decide.

• Ask one question first: will you live on the property? If yes, and you have an unused bedroom or attached garage, a JADU is usually the smartest, fastest first move.
• Spend on the private bathroom: it raises rent, makes the unit easier to rent and, under the 2026 rules, frees you from the owner-occupancy requirement.
• Remember you can build both: one ADU and one JADU on most single-family lots is often the highest-income setup for owners who live on site.

The ADU vs JADU decision always comes back to your plans, not just your lot. A short ADU feasibility study shows what your home can support.

Final Thoughts

A JADU is the affordable, fast path to legal rental income when you have unused interior space, especially with a private bathroom. An ADU costs more but delivers more space, higher rent, more flexibility and stronger resale value. Neither is better for everyone. The right answer in the ADU vs JADU choice is the one that matches your property and your plans. KN Remodeling designs and builds both, including garage conversions and detached ADUs, and we will walk your property and tell you honestly which unit your home can support.

ADU vs JADU FAQs