What shapes the cost of a garage conversion?
Two garages can need very different work. Before comparing estimates, define the space you want and what the existing structure needs.
What do published San Diego estimates suggest?
For a garage converted into a complete ADU, GreatBuildz estimates $150,000 to $230,000 in its October 2026 guide.
That source describes its range as including plans, permits, city fees, and construction; it identifies construction as one part of the total.
Separately, the San Diego ADU Guide estimates $125,000 to $250,000 or more for a garage conversion.
The latter guide describes a broad complete-project range, assuming a permitted garage with suitable structure and nearby utilities.
It says foundation corrections, moisture work, framing, and difficult sewer connections can change the budget.
These are third-party planning estimates, not quotes or a measured average. Neither source states a representative sample of completed projects, and neither establishes the price for your garage.
Do not assume the ranges include the same allowances, site restoration, financing, appliances, or unanticipated repairs. Ask each professional what is included and excluded for your property.
How to compare the scope behind a proposal
A room that remains part of the home can have a different scope from an independent ADU. Request an itemized proposal before setting a budget.
A bedroom or office connected to the home differs from an independent dwelling. Adding a kitchen, bathroom, or separate entrance can change the work and approvals required.
Tell each professional how you intend to use the space so their proposals cover the same goal.
The slab, walls, roof, door opening, and available ceiling height affect what can be reused and what needs work. A contractor should assess the property before giving a project-specific estimate.
Existing electrical capacity and the distance to water and sewer connections can also influence the scope.
Ask who will prepare drawings, handle permit applications, and coordinate inspections. Request an itemized allowance for fees and confirm them with the agency that reviews your address. The City of San Diego provides an ADU information bulletin; other jurisdictions have their own application procedures.
Review demolition, utilities, heating and cooling, insulation, windows, finishes, cleanup, and permit responsibility. Ask what is excluded, how changes are priced, and when payments are due. A lower initial estimate may leave out work included in another proposal. Garage Conversion SD is a referral service; you contract with the independent professional you choose. Verify the contractor’s license at cslb.ca.gov before signing.
Frequently asked questions
Why do garage conversion estimates vary?
The intended use, garage condition, utility routes, finishes, and required approvals can change the scope. Ask each professional to price the same project details.
What should I ask a professional to include in an estimate?
Ask about drawings, permits, utilities, finishes, allowances, exclusions, and how changes are priced. Confirm agency fees with the reviewing department.
Are the published ranges a quote for my project?
No. The ranges cited here are third-party planning estimates. A professional needs to assess the property and proposed work before giving a project-specific price.
Ready to discuss your conversion?
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