Garage Conversion Cost: $15,000–$120,000 by Type and State (2026)

A basic garage conversion — insulation, drywall, flooring, and an electrical panel upgrade — runs $15,000–$30,000 for a standard two-car garage. You're essentially making the space habitable, not livable. No bathroom, no kitchen, no dedicated HVAC. Good for a home office, gym, or workshop.

A full living space with a half bath costs $30,000–$60,000. This is the most popular conversion type. You get a real room with climate control, a toilet and sink, proper flooring, and finished walls. At mid-range quality it's a legitimate bedroom, guest suite, or rental room (where local zoning allows). The bathroom alone runs $8,000–$15,000 of that total.

ADU conversions are in a different category. A fully permitted garage ADU with kitchen, full bath, separate entrance, and finished interior runs $60,000–$120,000+. California has seen these costs spike to $100,000–$180,000 in the Bay Area and Los Angeles due to permit complexity, seismic requirements, and labor costs. But the payoff is real: ADUs in those markets rent for $1,500–$3,000/month, which pencils out fast.

The condition of your existing garage is the biggest wildcard. A clean, recently built attached garage costs 20–30% less to convert than a detached 1960s garage with outdated wiring, no insulation, and a cracked slab. Always get a structural and electrical assessment before committing to a budget.

Permits are not optional. Converting garage space to living space requires a building permit, and any plumbing or electrical work triggers separate trade permits. Budget $2,000–$8,000 for permits depending on your city, and factor in 4–12 weeks for approval. In California, cities are legally required to approve ADU permits within 60 days — but the initial back-and-forth with plan check can stretch timelines significantly.

ADU legality varies by state. California has the most permissive ADU laws in the country: cities cannot ban garage ADU conversions, and owner-occupancy requirements were eliminated in 2020. Texas, Florida, and most of the Southeast leave ADU rules to local municipalities — some cities allow them, most don't. Check your local zoning ordinance before planning an ADU conversion. A $90,000 project becomes worthless if the city won't approve it.

Setback requirements matter for detached garages. Converting a detached garage to an ADU requires meeting minimum setbacks from property lines — typically 4–5 feet on the sides and rear in California, more elsewhere. If your garage is too close to the fence line, you may need to reduce its footprint or wall off part of it. An architect or permit expediter ($1,500–$4,000) can tell you in a day whether your project is feasible.

One underrated cost: parking replacement. Many municipalities require replacing the off-street parking you're converting. That can mean adding a carport ($5,000–$15,000) or tandem parking, which adds real cost. Cities in transit corridors increasingly waive this requirement, so check your specific address.