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Know what your garage conversion should cost

A 400 sq ft garage conversion costs $25,800 to $42,200 in 2026, about $85 per sq ft installed. Across every option it runs from $13,200 (bonus room) to $128,800 (full adu).

Four questions gets you an itemised range, adjusted for construction wages where you live. The whole number, up front, before we ask for anything.

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What garage conversion work costs in 2026

ProjectTypical range
Bonus room Gym, office or playroom, no plumbing, no permanent HVAC $15,500 – $25,300
Habitable room Bedroom or guest room: insulation to code, egress, mini-split $25,800 – $42,200
Suite with bathroom Adds a full bath and the drainage to serve it $38,800 – $63,200
Full ADU Independent unit: kitchen, bath, sub-panel, own entrance $59,400 – $97,000

Where the money goes

Framing and insulation

$6,120 · 18% of the job

Drywall and ceiling

$4,760 · 14% of the job

Permits and inspections

$4,760 · 14% of the job

Electrical and lighting

$4,420 · 13% of the job

Heating and cooling

$4,080 · 12% of the job

Flooring

$3,740 · 11% of the job

Garage door infill

$3,400 · 10% of the job

Windows and doors

$2,720 · 8% of the job

Garage Conversion cost by state

Labour is the part of this job that moves with geography. These are the same 400 sq ft project, priced against construction wages in each state.

All 51 states and DC →

Questions homeowners ask

How much should I pay for a garage conversion?

For a standard 400 square foot garage turned into a habitable room at mid-range finishes, expect roughly $25,800 to $42,200. A gym or office with no plumbing runs far less, about $12,200 for a single-car garage. A full ADU in a two-car garage is closer to $86,000.

Is it cheaper to convert a garage or to build an addition?

Converting is cheaper, usually by a wide margin. The garage already has a foundation, walls and a roof. A 400 square foot habitable conversion runs about $34,000 at mid-range, where a 400 square foot ground-floor addition is closer to $82,000. The trade-off is losing the parking, which some buyers care about.

What makes a garage conversion legal to sleep in?

An egress window or door, insulation to code, a permanent heat source and a ceiling height that meets local minimums. The egress window alone runs about $5,500. Skipping permits is what turns a conversion into a problem at resale.

Do I need to remove the garage door?

For a habitable room, yes, framing and sealing the opening is about 10% of a typical conversion budget, or roughly $4,200 as a standalone job. Some owners keep the door on a bonus room to preserve the option of converting back.

Reviewed and maintained by Anchorcost. Last checked September 3, 2026. Figures are verified against this page's own calculator on every build. How these figures are worked out.