Estimate an attached one, two or three car garage by size, finish level and state, with add-ons and an optional room above.
Last updated: November 9, 2026
| 1-car, 264 sq ft | $26,400–$39,600 |
| 2-car, 576 sq ft | $57,600–$86,400 |
| 3-car, 864 sq ft | $86,400–$129,600 |
National average at $100–$150 per sq ft, before your state’s cost level.
Pick a size and finish level, then press Calculate to see your range.
An attached garage addition costs about $50 to $200 per square foot nationally. That puts a one-car garage at $13,200 to $52,800, a two-car garage at $28,800 to $115,200 and a three-car garage at $43,200 to $172,800, before your state's cost level is applied.
The table splits the national range into three finish bands. Your state moves every number up or down; the calculator applies that for you.
| Garage | Basic ($50–$100/sq ft) | Standard ($100–$150/sq ft) | Premium ($150–$200/sq ft) |
|---|---|---|---|
| 1-car, 12 x 22 (264 sq ft) | $13,200–$26,400 | $26,400–$39,600 | $39,600–$52,800 |
| 2-car, 24 x 24 (576 sq ft) | $28,800–$57,600 | $57,600–$86,400 | $86,400–$115,200 |
| 3-car, 36 x 24 (864 sq ft) | $43,200–$86,400 | $86,400–$129,600 | $129,600–$172,800 |
Sizes in the calculator are common footprints, not code minimums. Measure the space you want and use Custom if yours differs.
An attached garage is built to the fire-separation rules in the 2021 International Residential Code. These lines explain some of the gap between a garage kit price and a finished bid.
Your town may have adopted a different code edition or local amendments, so confirm with the building department before you price the plans.
A bonus room or apartment over a new garage is priced separately in the calculator at $325 per square foot, the same rate our second story calculator uses for a suite over a garage. It is adjusted for finish level and state, and shown as a range from 10 percent under to 20 percent over.
If a room above is likely later, say so at the design stage. The ceiling between a garage and a habitable room above has to be 5/8-inch Type X gypsum board, and the structure carrying that floor needs its own protection. If the room will be rented or used as an in-law unit, check the ADU calculator and your local accessory dwelling rules first.
The 2025 Cost vs Value Report puts a garage door replacement at a national average job cost of $4,672, the highest return of the 28 projects it tracks at 268 percent of cost recouped. That figure is for replacing a door, not building a new opening, but it is a useful check on the door line in a new-garage bid.
A two-car garage with two single doors instead of one double door needs a second door and opener, so ask which layout each bid assumes.
"i feel like under 50k would be hard to find these days,"Reply in r/Columbus, "Cost of building detached 2-car garage," September 2026 (54 upvotes)
Our take: a 576 sq ft two-car garage at the standard finish level in Ohio comes out at about $57,000 to $85,500 in this calculator, so the commenter's floor matches. That thread is about a detached garage; add the cost of running power out from the house.
"A pole barn is much simpler construction than a framed and sided two car garage in the city so that's not super surprising"Reply in the same r/Columbus thread (20 upvotes)
Our take: this calculator prices a framed, sided garage attached to the house. A post-frame building quoted by the square foot is a different product and should not be compared with these numbers.
No public national survey prices garage additions. The 2025 Cost vs Value Report has no garage addition project; its only garage item is door replacement. The calculator therefore uses the ranges published on this site and states where each one comes from.
Not included: a driveway or apron, demolition, a long power run to a detached garage, plan and permit fees, and site problems such as rock or a steep slope.
It prices an attached garage built on a new slab: framing, roof, a garage door and basic electrical, adjusted for finish level and your state, plus any add-ons you tick and an optional room above. It does not price a driveway, demolition, or plan and permit fees.
Only as a starting point. Our published ranges are for attached garages. A detached garage needs power run out from the house, and that cost depends on the distance, so add it to the estimate.
Common reasons are a sloped lot that needs more concrete, a roof tie-in to a complex existing roofline, a driveway, a long electrical run, or upgrades the calculator does not list. Ask for an itemized bid and compare it line by line with the breakdown.
Yes. Tick Room above the garage and enter its size. It is priced at the same per-square-foot rate as the suite-over-garage option in our second story calculator, adjusted for finish and state.
Some price a garage kit or materials only. This calculator prices a finished, contractor-built attached garage, which includes the slab, labor and the garage door.