Cost estimate · Concrete slab
Concrete Slab Cost Calculator
Price a garage, patio, shed, or shop slab from length, width, and thickness — with rebar and edge forms called out as their own lines. National US ranges; not a contractor bid.
Slab dimensions
Estimated slab cost
$2,622–$7,253
Typical ~$4,938 · $5–$13/sq ft
- Volume (raw)
- 7.11 cy
- With waste
- 7.47 cy
- Slab area
- 576 sq ft
Cost breakdown
- Ready-mix concrete (delivered)7.47 cy × $130–$200/cy$971–$1,493
- Labor — place & finish576 sq ft × $2.50–$8.00/sq ft$1,440–$4,608
- Rebar / wire mesh576 sq ft × $0.20–$1.50/sq ft$115–$864
- Formwork96 lf perimeter × $1.00–$3.00/lf$96–$288
Not included
- Excavation and grading
- Base gravel / compacted subbase
- Removal of existing concrete
- Permits and inspections
- Difficult site access or pumping beyond a standard day rate
- Vapor barrier, insulation, and control-joint saw cutting
Price data updated . National US ranges from published supplier and contractor averages. Not a bid. Local quotes vary.
How slab cost is calculated
A slab is still a rectangular prism. Thickness is the variable that moves yardage fastest — going from 4 in to 6 in is a 50% jump in concrete before you touch labor.
slab cu ft = length × width × (thickness_in ÷ 12) slab cu yd = slab cu ft ÷ 27 order yards = slab cu yd × (1 + waste %) material = order yards × ready-mix $/cy labor = area × place-and-finish $/sq ft rebar/mesh = area × reinforcement $/sq ft (optional) forms = perimeter × forms $/lf (optional)
Worked example. A two-car garage slab at the default 24 × 24 ft × 4 in is 24 × 24 × (4 ÷ 12) = 192 cubic feet, or 7.11 cubic yards. With 5% waste you order about 7.47 cy — above the short-load threshold. Ready-mix alone is roughly $971–$1,494. Labor on 576 sq ft at $2.50–$8/sq ft adds another $1,440–$4,608 before steel and forms. That labor band is why two garage quotes can look wildly different with the same yardage.
Concrete slab thickness guide
Pick a type in the calculator to pre-fill thickness and a sensible reinforcement default. Confirm against local code and soil conditions.
| Use | Thickness | Reinforcement | Notes |
|---|---|---|---|
| Patio or sidewalk | 4" | Wire mesh or fiber often sufficient | Over compacted gravel base; slope for drainage. |
| Garage floor slab | 4" | #3–#4 rebar or WWM at mid-depth | Thicken edges under walls; vapor barrier common. |
| Shed / equipment pad | 4" | Mesh or light rebar grid | Isolate from building footing if required. |
| Light vehicle driveway apron | 5" | Rebar grid recommended | Poor soils or heavier vehicles → 6 in. |
| Shop / light commercial floor | 6" | Engineered rebar layout | Point loads and racking need design. |
Concrete slab cost FAQ
- How thick should a concrete slab be?
- Most residential patio, sidewalk, and garage slabs are poured 4 inches thick over compacted base. Driveway aprons and light vehicle areas often go to 5 inches; shop floors with point loads may need 6 inches and an engineered layout. Local frost depth and soil conditions can change the design — this tool estimates cost, not structural adequacy.
- Does a slab cost calculator include the footing or stem wall?
- No. This page prices a flat rectangular slab: ready-mix, place-and-finish labor, and optional rebar, edge forms, pump, and stamped uplift. Turned-down footings, mono-pour thickened edges beyond a simple rectangle, and basement walls are separate scopes.
- Do I need rebar in a garage slab?
- Wire mesh or a light rebar grid at mid-depth is common for garage floors to control cracking from vehicle loads and shrinkage. Fiber-reinforced mixes help with plastic shrinkage but do not replace structural steel where an engineer specifies it. The calculator’s rebar line is a national $/sq ft range for material and tying.
- What about vapor barriers and insulation under the slab?
- Many garage and interior slabs sit on a polyethylene vapor retarder; some climates add rigid foam for energy code. Those materials and the labor to place them are not in the totals — they vary too much by code and product. Ask your contractor to line-item them separately when you compare bids.
- How are control joints factored into cost?
- Saw-cut or tooled control joints are usually part of place-and-finish labor on a simple slab. Decorative scoring, early-entry saws on large floors, or epoxy joint filler for warehouse slabs can add cost and are not modeled as a separate line here.
Driveway or small pad instead?
Long narrow pours and AC pads have different defaults. Driveway cost calculator · Pad cost calculator · General concrete cost