Short answer. A two-car garage to ADU conversion in Los Angeles runs $120,000 to $220,000 in 2026. A one-car conversion runs $90,000 to $150,000. The biggest cost variables are foundation condition, utility upgrades, and finish level.
Garage conversions are the fastest path to a permitted ADU in Los Angeles. The shell exists. The setback is already legal. California law removed the parking-replacement penalty. For homeowners who want rental income or a private guest unit without committing to a full ground-up build, this is the highest-ROI ADU path on the lot.
Cost ranges by garage size and scope
| Garage size | Typical ADU size | 2026 cost range |
|---|---|---|
| One-car (200 to 280 sq ft) | 200 to 280 sq ft studio | $90,000 to $150,000 |
| Two-car (380 to 480 sq ft) | 1 bed 1 bath | $120,000 to $220,000 |
| Two-car with addition | 500 to 750 sq ft 1 to 2 bed | $160,000 to $280,000 |
| Three-car or tandem | up to 1,000 sq ft | $200,000 to $340,000 |
Line items inside a $180,000 two-car conversion
| Line item | Typical share | Dollar range |
|---|---|---|
| Foundation retrofit and slab work | 8 to 14 percent | $14,000 to $25,000 |
| Framing, insulation, drywall | 15 to 22 percent | $27,000 to $40,000 |
| Roofing and exterior repairs | 5 to 10 percent | $9,000 to $18,000 |
| Plumbing rough and fixtures | 8 to 12 percent | $14,000 to $22,000 |
| Electrical and panel upgrade | 7 to 12 percent | $13,000 to $22,000 |
| HVAC mini-split system | 4 to 7 percent | $7,000 to $13,000 |
| Kitchen cabinets and counters | 8 to 12 percent | $14,000 to $22,000 |
| Bathroom finishes | 5 to 8 percent | $9,000 to $14,000 |
| Flooring and paint | 5 to 8 percent | $9,000 to $14,000 |
| Windows and exterior door | 3 to 6 percent | $5,000 to $11,000 |
| Permits and design | 6 to 10 percent | $11,000 to $18,000 |
| Project management | 6 to 10 percent | $11,000 to $18,000 |
Permit costs and process at LADBS
- Plan check fee. $1,500 to $3,500 depending on valuation.
- Building permit fee. $2,500 to $5,500 depending on city zone.
- Sewer cap and utility fees. $0 to $4,000 if separate meter.
- Plan check duration. 4 to 10 weeks. Faster on ADU express programs.
Where conversions go wrong
- Hiding foundation issues. A cracked slab or missing footing must be retrofit before drywall. Skipping this hurts the appraisal and creates moisture problems.
- Underbuilt electrical. The main panel often cannot carry the new ADU load. Plan for a panel upgrade if the house has a 100-amp main service.
- No insulation in the slab. Garage slabs were never designed for living space. Plan for sub-slab vapor barrier and rigid foam at the perimeter.
- Choosing the cheapest bid. Garage conversions reward thorough scope and detailed drawings. Bids that come in 30 percent below the others usually leave foundation and electrical out of scope.
For broader ADU pricing, see ADU cost in Los Angeles. For California-wide ranges, read how much does an ADU cost in California. To verify your contractor, run the CSLB license lookup. Then start the build process on the garage conversions service page.
