Is converting a garage cheaper than building a detached ADU from scratch?

Usually, yes. You're reusing an existing foundation, roof, and walls, which cuts out some of the biggest cost drivers of new construction. The savings shrink if your garage is detached and needs new utility trenching, or if the foundation needs to be reinforced.

Do I need a permit to convert my garage into living space?

Yes. Converting a garage to livable space, and especially to an ADU with a kitchen and bathroom, requires building permits and inspections in nearly every jurisdiction. Skipping permits can create problems later when you sell, since unpermitted work often has to be disclosed or corrected.

Can I convert my garage without adding a bathroom or kitchen?

Yes — a basic conversion to a bonus room, office, or bedroom without plumbing is generally the least expensive option, typically $50 to $100 per square foot. Adding a full kitchen and bathroom is what turns it into an ADU under most local zoning definitions, which brings in additional permitting requirements.

Will converting my garage hurt my home's resale value by removing covered parking?

It depends on your local market, but in many areas the added living square footage more than offsets the loss of a garage, particularly if the space is legally permitted as an ADU. It's worth weighing this against how ADUs generally affect property value in your area before committing to the conversion.

Does a detached garage cost more to convert than an attached one?

Generally yes, because a detached structure often needs new water, sewer, and electrical lines run underground from the house. That utility work alone can add 20% to 30% to the total project cost compared to an attached garage that's already close to existing utility connections.

How Much Does a Garage Conversion Cost in 2026?

Your garage is probably the cheapest square footage you'll ever turn into living space — the roof, slab, and walls are already built. That's why garage conversions are one of the most common ways homeowners add a rentable accessory dwelling unit (ADU) or extra bedroom without changing the footprint of the house. But "cheapest" is relative: what starts out simple can get expensive fast once electrical, plumbing, and permitting requirements kick in.

How Much Does a Garage Conversion Cost?

Nationally, converting a two-car garage (roughly 400–600 square feet) into a full ADU with a kitchen and bathroom runs $80,000 to $150,000, according to Angi's 2026 cost data. Per square foot, the price depends heavily on scope:

Conversion type	Cost per square foot
Basic living space, no plumbing	$50–$100
Space with a bathroom added	$100–$150
Full ADU (kitchen + bathroom)	$125–$200+

In California, plan on more: a basic 400-square-foot conversion often starts around $100,000, and a 650-square-foot unit with a full kitchen and bath can run $260,000, per the same data — driven by higher labor rates, code requirements, and permitting fees. High-end finishes (hardwood floors, stone countertops) can push per-square-foot costs toward $400 on either coast.

Attached or Detached: Why It Changes the Bid

If your garage is attached to the house, you're usually working close to existing water, sewer, and electrical lines. A detached garage is a different project: you'll likely need to run new utility lines underground from the house to the structure, and that alone can add 20% to 30% to your total cost. Before you get a number from any contractor, make sure they've actually walked the distance between your utility connections and the garage — that trenching is one of the most commonly underestimated line items in a bid.

Foundation condition matters just as much. Many garage slabs were poured to a different depth or thickness than a livable-space code requires, especially if the structure predates modern insulation and moisture-barrier standards. A contractor who skips this check can hand you a bid that looks competitive on paper and then grows once they open the slab and find it needs to be raised or repoured.

Will You Need an Electrical Panel Upgrade?

Almost always, yes. Adding HVAC, a kitchen, and modern appliances to a converted garage typically requires 100–200 amp service. If your home's main panel is 100 amps or smaller — common in older houses — you'll need a panel upgrade before any of the rest of the electrical work can happen, which typically adds $2,500 to $6,000 to the project. It's worth having an electrician check your panel capacity early, before you've priced out the rest of the job around a number that assumes your existing panel is sufficient.

What About Plumbing and Sewer Lines?

If you're adding a bathroom or kitchen, rough-in plumbing for a detached structure typically runs $10,000 to $25,000. A detached garage sitting at the back of a long lot can require significant trenching to reach the main sewer line, which can add another $5,000 to $15,000 on top of that. This is one of the biggest reasons two garage conversions of similar size can come back with wildly different quotes — the plumbing path, not the finishes, is often what separates an $80,000 project from a $150,000 one.

Do You Have to Replace the Parking You're Losing?

Not under California state law. Government Code Sections 65852.2 and 65852.22 prohibit cities from requiring replacement parking when you convert a garage into an ADU, according to the California HCD's official garage conversion guidelines. Rules outside California vary by city, so confirm your local ordinance before assuming the same protection applies where you live.

What Should You Budget for Permits?

Permit fees for a garage conversion ADU typically run $4,000 to $15,000, depending on project size, your jurisdiction, and any local surcharges layered on top of base fees, per permitting guidance for Los Angeles-area conversions. Because you're creating new legal housing rather than doing a simple remodel, expect line items for school, park, and sewer capacity fees that a standard room addition wouldn't trigger. If you're weighing a garage conversion against building a new detached unit, our ADU cost breakdown covers how the two compare on price per square foot.

What to Do About It

Before you commit to a number, get your specific garage assessed by more than one licensed contractor — not just a phone quote based on square footage. The gap between an $80,000 project and a $180,000 project usually comes down to three things a walk-through will reveal: whether the existing slab and foundation can be reused as-is, how far plumbing and sewer lines have to travel, and whether your electrical panel needs replacing before anything else can start.

A single quote only tells you what one contractor thinks the job is worth. Comparing two or three quotes on the same scope of work is what tells you whether a price is actually fair for your garage, your utility distances, and your city's permitting costs — instead of just hoping it is. If a bid comes back well outside these ranges without an explanation (like major trenching or a required panel upgrade), that's worth asking about directly. And because a garage conversion can add usable square footage to your home, it's also worth understanding how that affects resale value before you finalize the scope.

Getting comparable quotes from vetted, licensed pros is the fastest way to turn these national ranges into a real number for your specific garage.