Garage Build Cost Calculator

A standard two-car attached garage — the ≈ 20×24, 480 sq ft slab this calculator opens on — with one 16×7 insulated door, an opener, standard electrical, vinyl siding matched to the house, permit and drafted plans prices out around $27,459; the same garage detached runs about $29,460. A deeper 24×24 (576 sq ft) slab adds roughly $3,000. That brackets the published national numbers — Angi's 2026 guide puts professional garage construction at $16,837–$42,331 with a $29,584 average, and HomeGuide's full range is $15,000–$80,000 once large or finished builds are counted.

Attached — usually by 10–20%. A shared wall means one less exterior siding surface, no gutter run on that side and no trench for power: our two-car example prices at $27,459 attached vs $29,460 detached. The offset is code-required fire separation (Type X drywall on the shared wall and a self-closing fire-rated man-door), which adds only a few hundred dollars. Detached wins when you want living space above or a build farther from the house, but budget for the site work.

At the national base rate this model uses — $7.50 per sq ft for excavation, gravel, forms, a 4-in slab with thickened-edge footings, mesh and finishing — a 576 sq ft slab is about $4,320. Plan $1–$2 more per sq ft if you want 5–6 in of concrete or extra rebar for a car lift or heavy storage. The slab is typically 12–15% of a turnkey garage budget.

Yes — essentially every US jurisdiction requires a building permit for a new accessory structure, and most also check zoning setbacks, height limits and (for attached) fire separation. General building permits commonly run $525–$3,114 per Angi's permit pricing, more in high-cost metros. Skip it and you risk stop-work orders, denied insurance claims and a disclosure problem at sale; plans are usually the bigger line, $1,200 for stock/drafted drawings vs $3,200+ for architect-designed.

Calendar time is dominated by permits — 2–8 weeks depending on the city. Once approved, the physical build is fast: slab poured and cured in about a week, framing and trusses in 2–5 days, then roofing, siding, doors and electrical over another 1–2 weeks. Attached builds move quicker than detached because there's no trenching or separate foundation layout. Most homeowners should plan on 2–4 months door-to-door.

A metal or pole-barn kit shell runs $20–$35 per sq ft in materials — roughly half the stick-built turnkey rate — but that number excludes the slab, doors, openers, electrical and permit, so savings shrink once the site work is real. On a standard build the honest cuts are concrete, not structural: stepping from the standard electrical package to basic saves $1,450, and one shared 16×7 double door instead of two singles saves $650 — together about $2,100 off the default two-car build. Then vinyl instead of fiber cement and stock plans. The calculator's line items show exactly what each choice moves.

Yes if a plug-in car is anywhere in your future. Stepping from the standard electrical package to EV-ready (a 50-amp/240-volt circuit to the future parking spot) adds about $1,350 during construction vs $2,700+ retrofitting through finished walls later. If your main panel is full, an EV circuit may also force a subpanel or upgrade — the electrical panel calculator covers that decision.

The build is turnkey but unfinished: no insulation, drywall, heat or finished floor (our drywall calculator prices those walls); no driveway or apron (the asphalt driveway calculator covers that as its own project); no demolition of an existing shed or old garage; no landscaping repair; and no conditioned living space — a garage-to-ADU conversion is a different project with different numbers (see the ADU calculator). A 1-car build lands near $21,388 and a 3-car near $36,432 on the same specification as the defaults.