Garage Conversion Cost Guide for 2026/2027

Garage conversions are the most affordable ADUs — and the ones with the widest, most misunderstood price range. Here are the honest 2026/2027 planning numbers.

The three tiers

Owner-builder: roughly $80,000–$100,000. You act as your own general contractor — hiring trades directly, scheduling, managing inspections yourself. This saves the GC's overhead and profit but costs you months of part-time project management and all of the risk. Realistic only for organized owners with time, and for structurally simple garages. (Module 11 covers the owner-builder decision honestly.)

Licensed general contractor: roughly $100,000–$160,000 average. The standard path. A typical two-car conversion with sound structure, standard finishes, and no utility drama lands in this band. The spread inside the band is mostly finishes and bathroom/kitchen choices.

Higher-end or complicated: $160,000+. Triggered by the structural issues below, premium finishes, size expansion beyond the footprint, or utility upgrades. A conversion needing a new foundation plus a panel upgrade plus high-end finishes can approach small new-construction territory.

These numbers vary — by city, by year, by your garage's secrets. Treat them as planning bands and get real estimates before committing.

What moves you between tiers

The next lesson goes deep, but the headline factors: foundation condition (the big one), electrical panel capacity, plumbing distance, roof condition, and whether you expand the footprint.

The value math

Even at the top of the GC band, conversions usually deliver the cheapest legal rentable unit possible. $130K creating a unit renting for $1,800–$2,200/month in much of urban California is the kind of arithmetic that explains why every block in LA seems to have one underway.