Quick answer: a concrete slab costs about $7 to $13 per square foot installed in 2026, or $2.50 to $4.50 per square foot in materials if you pour it yourself. A typical 20x20 slab (400 sq ft, 4 inches thick) runs $2,810 to $5,060 installed. Driveways and garage floors cost more in total because they are thicker and larger, and small pads cost more per foot because fixed costs are spread over less area.

That headline range is a starting point, not a quote. The real price of your slab depends on its size, thickness and use, what is under it, how the truck gets to it, and how it is finished. This guide gives the benchmarks by size and by project type, shows where the money goes, explains what moves the price up or down in your area, and shows how to read a contractor's quote line by line. Every figure here comes from the same rates our slab cost calculator uses, so you can plug in your own dimensions and get the same answer.

Concrete Slab Cost by Size

Size (4 in thick)AreaConcrete to orderDIY materialsInstalledInstalled per sq ft
10 × 10 ft100 sq ft1.36 yd³$410 to $570$840 to $1,430$8.37 to $14.33
10 × 20 ft200 sq ft2.72 yd³$660 to $980$1,510 to $2,660$7.55 to $13.31
12 × 12 ft144 sq ft1.96 yd³$520 to $750$1,130 to $1,970$7.85 to $13.69
16 × 24 ft384 sq ft5.21 yd³$1,080 to $1,690$2,710 to $4,880$7.06 to $12.70
20 × 20 ft400 sq ft5.43 yd³$1,110 to $1,750$2,810 to $5,060$7.03 to $12.66
24 × 24 ft (2-Car Garage)576 sq ft7.82 yd³$1,500 to $2,430$3,950 to $7,170$6.86 to $12.45
30 × 40 ft (Shop/Barn)1,200 sq ft16.30 yd³$2,870 to $4,790$7,970 to $14,620$6.64 to $12.18
Installed low end: plain broom-finish slab with ready-mix at $150/yd³ plus a $120 delivery fee, forms and labor at $3.50/sq ft. High end: the calculator's default scope (adds a vapor barrier and #4 rebar at 18 in, labor at $5.00/sq ft) plus 25% contractor overhead and profit. DIY materials: the cheaper of ready-mix or $6.50 80-lb bags, plus forms, up to vapor barrier and rebar. Site excavation and a gravel base are extra (about $1.40 to $3.30 per sq ft). Concrete includes 10% waste.

Notice how the per-square-foot price falls as slabs get bigger. A delivery fee, a contractor's setup time and the forms around the edge are all paid once per job, so a 10x10 pad carries them on 100 sq ft while a 30x40 shop spreads them over 1,200 sq ft. For a closer look at the sizes people ask about most, see the 10x10, 12x12, 20x20 and 24x24 breakdowns.

Cost by Thickness

Thickness changes only the concrete line, so it moves the total less than people expect. On the 20x20 reference slab:

ThicknessTypical useConcrete to orderInstalled
4 inPatios, walkways, shed floors5.43 yd³$2,810 to $5,060
5 inDriveways, garage floors6.79 yd³$3,010 to $5,320
6 inRV pads, shops, heavy hot tubs8.15 yd³$3,220 to $5,570

IRC section R506 sets 3.5 inches as the minimum for a concrete floor on ground. Our thickness guide explains which thickness fits which load.

Cost by Project Type

ProjectReference slabPer sq ft installedTypical total
Patio or shed pad20 × 20 ft, 4 in$7 to $13$2,810 to $5,060
Driveway (2-car)20 × 40 ft, 5 in$7 to $13$5,820 to $10,380
Garage floor24 × 24 ft, 5 in$7 to $14$4,250 to $7,540
Monolithic house or shop foundation30 × 40 ft, 4 in floor, thickened edge$7 to $14$8,400 to $16,800
Stamped patio20 × 20 ft, 4 in$13 to $22$5,200 to $8,800
Per-square-foot ranges are rounded outward to whole dollars. Totals for the foundation and stamped rows are the per-square-foot range times the reference area.
  • Patios are the simplest slab: 4 inches, often mesh instead of rebar, and no vapor barrier. Finish is the big variable. See the patio cost guide.
  • Driveways are 5 inches with rebar and usually 3,500 to 4,000 PSI air-entrained concrete in cold climates. See the driveway cost guide.
  • Garage floors match driveways in thickness but add a vapor barrier, and the walls need footings. See the garage slab cost guide.
  • Foundations add a thickened perimeter footing poured with the floor; frost depth decides whether that is allowed. See the monolithic slab guide.

Where the Money Goes

Here is the full-scope 20x20 slab broken into its line items. This is the calculator's default scope and the benchmark our quote checker compares bids against:

Line itemCostShare of direct cost
Placing and finishing labor$2,00049%
Ready-mix concrete and delivery$93523%
#4 rebar grid$50012%
Broom finish$3007%
Forms$1764%
Vapor barrier$1403%
Direct cost$4,051All

Labor is the biggest single line, close to half the direct cost, and it is also the line that varies most between regions. Concrete is the second. Contractors then add overhead and profit; a markup of up to about 25% over direct cost is normal. Want the same numbers per unit? The cost per square foot matrix breaks them down by area, and the cost per cubic yard guide covers ready-mix pricing by strength.

What Moves the Price in Your Area

The benchmarks above assume an open, fairly flat site with good truck access. These are the factors that push a real job up or down, with their effect on the 400 sq ft reference slab:

FactorTypical rateEffect on a 20x20
Excavation and compacted gravel base$1.40 to $3.30/sq ft$560 to $1,320
Removing an old slab$3 to $4/sq ft$1,200 to $1,600
Pump when the truck cannot reachLine pump per job$400 to $800
Stronger concrete (4,000 PSI)$4 to $10/yd³ per 500 PSI$40 to $110
Hard site (slope, tight access, wheelbarrows)Labor $7.50/sq ft instead of $5.00about $1,000
Stamped finish instead of broom$7.50/sq ft instead of $0.75$2,700 to $3,380
Short-load fee on small ordersFlat fee$80 to $200
Permit (where required)Flatwork permit$50 to $350

Regional differences show up mostly in labor and ready-mix prices. Finishers earn roughly $40 to $70 an hour depending on the market, and ready-mix for standard 3,000 PSI concrete runs about $135 to $160 per yard. Large metro areas and remote rural areas both tend to sit at the high end: one for labor, the other for delivery distance. Season matters too. Below about 40°F, ACI 306R cold-weather practice calls for protection such as blankets or heated enclosures, and many crews add a charge for it. In spring, busy contractors quote higher. Our guide to the best time to pour covers the timing side.

DIY vs. Hiring a Contractor

Doing it yourself saves the labor line and the contractor's markup, which together are most of the bill. On the 20x20, DIY materials run $1,110 to $1,750 against $2,810 to $5,060 installed. The trade-off is risk: concrete gives you one chance, and a slab that is out of level or badly finished costs more to tear out than the labor you saved. Small pads up to about 12x12 are realistic first projects. Driveways, garage floors and anything structural are usually better hired out. See what you can and shouldn't DIY.

How to Read a Concrete Quote

Two quotes for the "same" slab can differ by thousands because they are not quoting the same job. Before comparing prices, make sure each quote states:

  • Dimensions, thickness and area. A 4-inch and a 5-inch slab are different jobs.
  • Concrete strength and volume. PSI grade, whether it is air-entrained, and the yards ordered.
  • Reinforcement. Rebar size and spacing, or mesh, and whether it sits on chairs.
  • Base and site prep. Excavation depth, gravel type and thickness, and compaction. This is the line most often left out.
  • Vapor barrier, finish, control joints and curing. Joint spacing and timing of saw cuts.
  • Extras: pump, demolition, haul-off, permit, and who pays if the truck waits.

As a rough test, a fair full-scope price for the 20x20 reference slab sits between its direct cost of $4,051 and that plus 25% overhead and profit, $5,064, before site prep. A quote well above that should come with a reason (difficult access, a deep base, a decorative finish). One well below it may be leaving something out. Our concrete quote checker runs this test for your exact slab.

Sources and Method

Costs are built from line items (ready-mix, delivery, forms, vapor barrier, rebar, finish and labor) at this site's working benchmark rates; our methodology explains where they come from. They are planning figures, not quotes, and local prices vary by region and season. Code and practice references: International Residential Code section R506 (slabs on ground), section R403 (footings) and Table R402.2 (concrete strength); ACI 302.1R (floor and slab construction); ACI 306R (cold weather); ASTM C94 (ready-mixed concrete).

Frequently Asked Questions

About $7 to $13 per square foot installed, or $2.50 to $4.50 per square foot for materials if you do it yourself. Small slabs cost more per foot, and site prep is extra.

A 20x20 slab 4 inches thick costs about $2,810 to $5,060 installed, or $1,110 to $1,750 in DIY materials. At 5 inches, for a garage floor, it is about $3,010 to $5,320.

Labor. On a 20x20 slab, placing and finishing labor is about 49% of the direct cost, and ready-mix concrete with delivery is about 23%.

Often not. Excavation and a compacted gravel base add about $1.40 to $3.30 per square foot. Check that your quote lists base depth and compaction.

A monolithic slab foundation with a thickened edge costs about $7 to $14 per square foot. Frost depth in your area decides whether a thickened edge is allowed or a deeper footing is required.

A stamped slab costs about $13 to $22 per square foot installed, compared with $7 to $13 for a broom finish.

Calculate Your Concrete Project Budget

Use our comprehensive concrete slab cost calculator to get a complete line-item breakdown of materials, labor, reinforcement, and base preparation.

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Slab Estimating & Editorial Engineering Team

Construction Cost Estimators & Civil Engineering Analysts
Our team specializes in structural flatwork estimating, concrete mix designs, and civil building codes (ACI 302.1R, ASTM C94). All calculators and cost guides are rigorously validated against live contractor material price sheets, regional aggregate indexes, and real-world project bids.