Garage Cost Calculator

A garage cost calculator that prices an attached or detached build by the bay: slab, framing, roof, siding, the doors and openers, electrical and the permit.

By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.

Quick answer: A garage is priced as a shell by the square foot, then the doors, the electrical and the permit. A 24 x 24 ft detached two car garage with a new slab, one 16 x 7 ft door and an unfinished interior runs about $29,800 to $60,700. That is $14,900 to $30,400 per car, or $51.78 to $105.44 per square foot.

Your measurements

A rectangular volume: length times width times depth.

BaysSets the footprint. One bay is 14 x 24 ft, two bays 24 x 24 ft and three bays 32 x 24 ft. All three stay 24 ft deep, which leaves a bench along the back wall.Attached or detachedAttached drops one wall and the trench but buys the fire separation IRC R302.6 sets and the self-closing door R302.5.1 sets. Detached needs a fourth wall and a buried feeder.Over the baysAttic trusses and a pull-down stair turn the roof space into storage. A finished room above an attached garage puts 5/8 in Type X gypsum on the garage ceiling under IRC R302.6.Floor slabA garage slab runs 4 to 5 in over a compacted base with a thickened edge, or on frost walls where the ground freezes. Pick the existing option only if the slab is sound and sized for the new walls.Number of vehicle doorsCount openings, not cars. Two singles cost more than one double but let you take either car out without moving the other.Door size9 x 7 ft is the single most builders hang now and 16 x 7 ft is the standard double. Go to 8 ft of height for a lifted truck, a van with a roof rack or a lift.Interior finishMost garage bids stop at the shell with the studs showing. Insulation only pays once there is a heat source, and an attached garage still gets its separation wall covered either way.ElectricalNEC 210.11(C)(4) asks for at least one 20 A branch circuit for the garage receptacles and 210.52(G)(1) asks for a receptacle in each bay. A detached garage also needs a buried feeder.

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Installed cost range$29,800 to $60,700All results

Results

Installed cost range: $29,800 to $60,700; 576 sq ft detached 2 car garage at 24 ft x 24 ft, an unfinished interior
Cost per car: $14,900 to $30,400 per bay; A second bay buys slab, roof and siding, but no second feeder, service door or permit, so cost per bay falls as bays are added.
Cost per square foot: $51.78 to $105.44 per sq ft; A garage sits well under finished living space by this measure, with no plumbing, no ductwork and no floor covering. Contractors compare bids on this line.
Shell: slab, framing, roof and siding: $23,328 to $44,585; Slab $4,608 to $8,640 over 576 sq ft. 864 sq ft of new wall, 713 sq ft of roof at a 4/12 pitch with 1 ft overhangs, 731 sq ft of siding
Doors and openers: $3,000 to $6,650; 1 sectional door at 16 x 7 ft, $1,900 to $4,200 each, plus 1 opener at $400 to $850, and a steel service door at $700 to $1,600. Headers over 16 ft of opening sit in the framing line
Electrical: $3,000 to $7,700; A subpanel gives the garage its own breakers for lights, receptacles and a compressor. A feeder trenched from the house adds $1,600 to $4,500 over about 50 ft of trench, below the local frost line
Interior finish: Shell only, framing exposed; Drywall and paint over 1,328 sq ft of wall and ceiling would add $3,984 to $7,304, and insulation another $2,125 to $4,250 on top
Permit, plans and inspections: $500 to $1,800; Plan review plus footing, framing, electrical rough and final inspections. IRC R105.2 exempts only a one-story detached accessory building of 200 sq ft or less, which no garage reaches
What it adds at appraisal: Not counted as living area; Fannie Mae Selling Guide B4-1.3-05 has appraisers measure under ANSI Z765-2021, which keeps garage floor area out of gross living area. The garage is adjusted on its own line of the sales comparison grid instead.

Garage Cost formula

Shell = Slab area x $8 to $15 + Wall area x $7 to $13 + Roof area x $11 to $20 + Siding area x $6 to $13
Wall area = (Perimeter - shared wall) x Wall height;  Roof area = (Width + 2) x (Depth + 2) x 1.054 for a 4/12 pitch
Doors = Door count x (door price + $400 to $850 opener), plus one service door
Attached adds Shared wall area x $3 to $5.50 of gypsum plus a rated self-closing door; detached adds $1,600 to $4,500 of trenched feeder
Permit = the greater of $500 or 0.8 percent of construction cost, up to the greater of $1,800 or 2.2 percent
Total = Shell + Doors + Electrical + Interior finish + Fire separation + Space above + Permit

Worked example

A one car attached garage, 14 x 24 ft, with a storage loft on attic trusses and a new slab. It gets one 9 x 7 ft door, a drywalled interior and its own subpanel.

The shared 24 ft wall drops out, so only 52 ft of new wall goes up. At 10 ft tall for the loft that is 520 sq ft of framing at $7 to $13. The roof measures 16 x 26 ft on plan times 1.054, or 438 sq ft, and siding covers 457 sq ft once the door opening comes out. The shell lands at $14,145 to $27,050. The door and opener add $1,600 to $3,350, and the subpanel $1,400 to $3,200 with no trench to dig. Drywall over 793 sq ft of wall and ceiling costs $2,379 to $4,362.

The separation line is 240 sq ft of gypsum on the shared wall plus the rated self-closing door, or $1,170 to $2,420. The loft adds $4,032 to $8,064. With the permit the job runs about $25,200 to $50,200, which is $75.08 to $149.54 per square foot. One bay carries every fixed cost on its own, which is why a single garage never looks cheap by the foot.

Quick reference

Typical 2026 US installed range, new slab, a subpanel and an unfinished garage interior unless noted
Garage	Footprint	Doors	Installed range	Per bay
1 car detached	14 x 24 ft	One 9 x 7 ft	$22,000 to $45,500	$22,000 to $45,500
2 car attached	24 x 24 ft	One 16 x 7 ft	$25,900 to $51,600	$13,000 to $25,800
2 car detached	24 x 24 ft	One 16 x 7 ft	$29,800 to $60,700	$14,900 to $30,400
2 car detached, insulated and drywalled	24 x 24 ft	One 16 x 7 ft	$35,900 to $72,300	$18,000 to $36,100
3 car detached	32 x 24 ft	Three 9 x 7 ft	$38,000 to $76,400	$12,700 to $25,500
2 car detached, finished room above	24 x 24 ft	One 16 x 7 ft	$75,700 to $153,800	$37,900 to $76,900

Attached and detached are two different buildings

An attached garage borrows a wall, a roof edge and a power source from the house. On a two car footprint that removes about a quarter of the wall framing and siding. It also removes the trench, because the panel already sits on the other side of the shared wall. What it adds back is fire separation. IRC R302.6 wants at least 1/2 inch gypsum board on the garage side of that wall. Where a habitable room sits above the garage, the ceiling takes 5/8 inch Type X. IRC R302.5.1 wants a self-closing, self-latching door into the house, in solid wood or solid or honeycomb core steel at least 1-3/8 inches thick, or a 20-minute rated door. R302.5.2 adds that any duct crossing the separation is No. 26 gage steel with no opening into the garage.

A detached garage is a whole small building. Four walls, four roof edges, its own service, and its own place on the lot. The lot is where most of them get stopped. Setbacks and IRC R302.1 fire separation distance decide whether the wall facing the line has to be rated. They also decide how far the eave can project, and the answer comes off the zoning map rather than the code book. Budget the feeder honestly. A buried run from the house panel to a subpanel typically costs $1,600 to $4,500 for about 50 feet of trench, below the local frost line. It is the line most homeowners forget until the electrician prices it.

The door, the opener and the value question

The door is the one line on a garage that no other building has, and it drives more than its own price. A 16 foot opening in a bearing wall needs a header sized for the roof load above it. On most garages that means engineered lumber rather than a doubled 2x10. Two 9 foot doors instead of one 16 foot double cost more in doors, openers and hardware. They also put a post between the openings, so either car comes out without moving the other. Height is the decision people regret. A 7 foot door clears a sedan and a stock pickup. An 8 foot door is what a lifted truck, a van with a roof rack or a future two post lift needs. Openers are governed by federal rule rather than by code. 16 CFR 1211.1 covers every residential opener made on or after January 1, 1993. Section 1211.7 makes a closing door reverse when it meets a 1 inch object on the floor. Under 1211.6 the opener either closes only under constant pressure or carries secondary protection meeting 1211.8, such as photoelectric sensors.

The value question is the real reason most people search this. A garage does not add square footage on an appraisal. Fannie Mae Selling Guide B4-1.3-05 has appraisers measure under ANSI Z765-2021, and garage floor area never enters gross living area. A detached garage is reported and adjusted on its own line of the sales comparison grid. It counts as a feature the market prices, not as living space. The exception is finished area above an attached garage with direct interior access and a conforming ceiling height, which can count in the square footage. That split is worth knowing before you choose between a room above and a bigger footprint. It is also why an unpermitted garage is worth less than nothing, since the appraiser leaves it out and the buyer's lender asks about it.

What this calculator leaves out

Site work comes first and is not here. Clearing, tree removal, grading, the driveway or apron from the street to the door, and any retaining or drainage the new footprint forces. It does not price demolition of an existing garage or slab, frost walls in place of a thickened edge, a floor drain, or an epoxy floor coating. Gutters and downspouts, a second story stair, windows beyond a plain shell and an insulated door upgrade are all outside it. So is a wind load rated door where the local design pressure requires one. A hose bib, a car lift and the slab thickening it needs, cabinets, and the property tax reassessment on the new structure are also outside it. Setbacks, lot coverage limits, height limits and any HOA review decide whether the garage is allowed where you want it. None of that shows up in a cost per square foot.

Code limits that apply

IRC R302.6
1/2 in gypsum on the garage side of the house wall, 5/8 in Type X under habitable rooms
If you miss it: An attached garage ceiling hung in standard board under a bedroom fails the separation inspection and comes back down
IRC R302.5.1
Self-closing 1-3/8 in solid wood, honeycomb core steel or 20-minute rated door into the house
If you miss it: A hollow core passage door with no closer is the most common attached garage correction at final inspection
IRC R302.5.2
Ducts through the garage separation are No. 26 gage steel with no opening into the garage
If you miss it: A flex duct run through the garage ceiling to feed the room above pulls exhaust fumes into the house
IRC R309.1
Garage floor of noncombustible material, sloped to a drain or toward the main vehicle door
If you miss it: A dead flat slab holds meltwater and road salt against the door track and the treated bottom plate
IRC R105.2
The one-story, 200 sq ft or less permit exemption for a detached accessory building never reaches a garage
If you miss it: Unpermitted garage square footage is excluded at appraisal and surfaces at sale or at refinance
NEC 210.52(G)(1)
A receptacle outlet in each vehicle bay, not more than 5 1/2 ft above the floor
If you miss it: A garage wired with one ceiling light and no wall receptacle fails the rough electrical inspection
NEC 210.11(C)(4)
At least one 20 A, 120 V branch circuit serving the garage receptacle outlets
If you miss it: Garage receptacles tapped off a lighting circuit trip every time a compressor or a saw starts
16 CFR 1211.7
Openers made since 1993 must reverse a closing door on a 1 in high object on the floor
If you miss it: Down force turned up to stop a nuisance reversal leaves the door unable to reverse on a child or a pet

Provision	Limit	If you miss it
IRC R302.6	1/2 in gypsum on the garage side of the house wall, 5/8 in Type X under habitable rooms	An attached garage ceiling hung in standard board under a bedroom fails the separation inspection and comes back down
IRC R302.5.1	Self-closing 1-3/8 in solid wood, honeycomb core steel or 20-minute rated door into the house	A hollow core passage door with no closer is the most common attached garage correction at final inspection
IRC R302.5.2	Ducts through the garage separation are No. 26 gage steel with no opening into the garage	A flex duct run through the garage ceiling to feed the room above pulls exhaust fumes into the house
IRC R309.1	Garage floor of noncombustible material, sloped to a drain or toward the main vehicle door	A dead flat slab holds meltwater and road salt against the door track and the treated bottom plate
IRC R105.2	The one-story, 200 sq ft or less permit exemption for a detached accessory building never reaches a garage	Unpermitted garage square footage is excluded at appraisal and surfaces at sale or at refinance
NEC 210.52(G)(1)	A receptacle outlet in each vehicle bay, not more than 5 1/2 ft above the floor	A garage wired with one ceiling light and no wall receptacle fails the rough electrical inspection
NEC 210.11(C)(4)	At least one 20 A, 120 V branch circuit serving the garage receptacle outlets	Garage receptacles tapped off a lighting circuit trip every time a compressor or a saw starts
16 CFR 1211.7	Openers made since 1993 must reverse a closing door on a 1 in high object on the floor	Down force turned up to stop a nuisance reversal leaves the door unable to reverse on a child or a pet

Rows marked checked produce a warning in the results when an entry crosses the limit. The others are on the plans or on site and this calculator does not test them. Local amendments can be stricter; the adopted edition and the inspector govern.

Mistakes that cost money

Sizing a 16 ft garage door header off a window table. That opening takes engineered lumber sized for the roof load above it.
Ordering a 7 ft door before you own the truck. A lifted pickup or a roof rack needs the 8 ft door and taller walls.
Drywalling an attached garage ceiling in standard 1/2 in board under a bedroom. IRC R302.6 wants 5/8 in Type X there, and the inspector checks.
A hollow core passage door into the house with no closer. IRC R302.5.1 wants a self-closing, self-latching rated door there.
Pouring the garage slab dead flat. IRC R309.1 wants the parking area sloped to a drain or toward the main vehicle door.
Setting a detached garage tight to the property line. Setbacks and IRC R302.1 decide the wall rating and how far the eave can project.

Key facts

A 24 x 24 ft detached two car garage with a new slab and one 16 x 7 ft door typically costs $29,800 to $60,700 in 2026. That is $14,900 to $30,400 per bay, or $51.78 to $105.44 per square foot.
IRC R302.6 requires at least 1/2 in gypsum board on the garage side of the wall separating an attached garage from the house. Where habitable rooms sit above the garage, the ceiling takes 5/8 in Type X gypsum board.
IRC R302.5.1 requires a self-closing, self-latching door between an attached garage and the house, and bans any opening from a garage into a sleeping room.
NEC 210.52(G)(1) requires a receptacle outlet in each vehicle bay, not more than 5 1/2 ft above the floor. NEC 210.11(C)(4) requires at least one 20 A branch circuit to serve them.
16 CFR 1211.1 covers every residential garage door opener made on or after January 1, 1993. Under 16 CFR 1211.6 those openers either close only under constant pressure or carry a secondary entrapment device meeting 16 CFR 1211.8, such as photoelectric sensors.
Fannie Mae Selling Guide B4-1.3-05 has appraisers measure under ANSI Z765-2021, so garage floor area is never counted in a home's gross living area.

Frequently asked questions

How much does it cost to build a 2 car garage?

A 24 x 24 ft detached two car garage with a new slab and one 16 x 7 ft door typically runs $29,800 to $60,700 in 2026. That assumes a subpanel and an unfinished interior. It works out to $14,900 to $30,400 per bay, or $51.78 to $105.44 per square foot. Insulating and drywalling it adds $6,109 to $11,554.

Is an attached garage cheaper than a detached one?

Usually yes. The same 24 x 24 ft garage attached runs about $25,900 to $51,600 against $29,800 to $60,700 detached, because it drops one wall, its siding and the trenched feeder. Part of that saving goes back into the fire separation IRC R302.6 and R302.5.1 require.

Does a garage add to a home's appraised value?

It adds value, but never square footage. Fannie Mae Selling Guide B4-1.3-05 has appraisers measure under ANSI Z765-2021, which excludes garage area from gross living area. A garage is adjusted as a feature on its own line of the sales comparison grid. Finished space above an attached garage with direct interior access is the one part that can count.

What size garage door should I order?

9 x 7 ft is the standard single and 16 x 7 ft the standard double. Choose 8 ft of height for a lifted truck, a van with a roof rack or a future lift. Decide before the header is framed, because changing it later means opening the wall.

Sources and references

Chapter 3 Building Planning, R302.5 and R302.6 dwelling-garage separation and R309 garages, 2021 IRC (ICC)
NFPA 70, National Electrical Code (garage branch circuits, receptacles and GFCI) (NFPA)
16 CFR Part 1211, Safety Standard for Automatic Residential Garage Door Operators (US Consumer Product Safety Commission)
Selling Guide B4-1.3-05, Improvements Section of the Appraisal Report (Fannie Mae)

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