Cost to Pour a Concrete Slab: Size, Yards and What's Included (2026)

Having a contractor pour and finish a concrete slab costs $6 to $12 per square foot installed, according to HomeGuide (February 2026), or $5,400 to $10,800 for a 30×30 slab. This Old House (March 2026) gives a lower range: “Concrete slab costs typically range from $4–$8 per square foot,” or $3,600 to $7,200 for 30×30. HomeGuide’s range is an installed price, labor included; This Old House doesn’t say what its range includes. So when you compare quotes against either one, check what each quote covers: thickness, base, reinforcement and finish.

Cost by slab size

Cubic yards are our math for a 4-inch slab, before any allowance for waste. HomeGuide’s column is its own table. The This Old House column is $4 to $8 multiplied by the area; the 20×30 and 30×30 rows are figures This Old House gives itself.

HomeGuide says its numbers come from “research and project costs reported by HomeGuide members.” Concrete Network, an industry site, gives a third range (July 2026): “Expect to pay between $6.50 and $10.50 per square foot to have a plain concrete slab poured.”

Cost by what the slab is for

This Old House gives no sizes for its averages. HomeGuide notes that “Most shed slabs are about 4 inches thick and do not typically require reinforcement or decoration,” and that most 2-car garage floors are reinforced concrete 4 to 6 inches thick. A slab for a garage or addition has its own page: concrete foundation cost.

How much concrete goes into it

Volume in cubic yards = length × width × (thickness in inches ÷ 12) ÷ 27. HomeGuide says a cubic yard “can cover 81 square feet of a 4-inch slab.”

Order more than the math says. The National Ready Mixed Concrete Association (NRMCA) advises: “Include an allowance of 4 to 10 percent over plan dimensions for waste, over-excavation and other contingencies.” Its example of why: “a 1/8-inch (3-mm) difference in a 4-inch (100-mm) thick slab would mean a shortage of 3 percent.”

What the concrete itself costs depends on whose figure you use:

HomeGuide’s yard guide also cites an NRMCA average of $108 per yard; the NRMCA price history on Concrete Network’s page lists $108 for 2016 and $180 for 2024. HomeGuide adds that a load under a full truck of about 10 yards “is considered a short load which adds $53 per cubic yard.”

Example, our math: a 20×20 slab at 4 inches plus NRMCA’s 4 to 10 percent is about 5.1 to 5.4 yards. At HomeGuide’s yard price plus its short-load fee ($172 to $200 a yard), that’s roughly $880 to $1,090 of concrete; at Concrete Network’s $179.95 average, before any short-load or delivery fee, about $920 to $980. For the same slab, HomeGuide’s installed price is $2,400 to $4,800 and This Old House’s range works out to $1,600 to $3,200; what’s above the cost of the concrete pays for the other lines below. Concrete cost per yard covers delivery fees in detail.

What the price includes, layer by layer

• Prepared ground. HomeGuide lists grading as a separate cost factor. Digging should wait for an 811 locate, requested “a few business days before you begin any digging,” per the national 811 service.
• Base. For home slab floors, the 2021 International Residential Code (IRC) calls for “A 4-inch-thick (102 mm) base course” of sand, gravel or crushed stone where the slab is below grade, with an exception for well-drained soils (R506.2.2). HomeGuide says “Some large concrete projects require a gravel base to prevent shifting and cracking.”
• Vapor barrier. The IRC requires a 10-mil vapor retarder under slab floors but not under “Driveways, walks, patios and other flatwork not likely to be enclosed and heated at a later date,” or under garages and other unheated accessory buildings (R506.2.3).
• Reinforcement. Wire mesh, rebar or thickened edges, where the job calls for them. Under the IRC, reinforcement must stay “from the center to upper one-third of the slab” while the concrete is placed (R506.2.4).
• The slab. The 2021 IRC sets a minimum of 3½ inches for slab-on-ground floors (R506.1); newer editions of the IRC exist, and your local code may differ. HomeGuide: “Most slabs are 4 to 6 inches thick.”
• Joints. NRMCA says “The maximum joint spacing should be 24 to 36 times the thickness of the slab,” which is about 10 feet for a 4-inch slab, and no more than 15 feet. Contraction-joint grooves should be at least ¼ of the slab’s thickness deep, “but not less than 1 inch.”

HomeGuide splits its $6 to $12 into materials at $3 to $7 per square foot and labor at $3 to $5, and says labor “includes concrete form creation.” What each layer adds per square foot (base, vapor barrier, mesh, rebar, thicker edges), source by source, is on concrete slab cost per square foot.

What moves the price

• Thickness. In HomeGuide’s table, the installed price rises from $6 to $8 per square foot at 4 inches to $10 to $12 at 8 inches. The full table, with This Old House’s figures beside it, is on the per-square-foot page linked above.
• Finish. HomeGuide: “Stamped concrete costs $8 to $19 per square foot installed, including pouring the slab.” See stamped concrete cost.
• Access. HomeGuide says “special equipment used for grading or pouring in hard-to-reach areas may increase labor costs.” A pump, if the truck can’t reach the pour, is another line.
• An old slab in the way. Removal is a separate line. HomeGuide: “Concrete removal costs $3 to $8 per square foot, including disposal,” and it suggests replacing concrete that is over 40 years old or shows large cracks, “Significant crumbling” or sinking edges.

What the written quote should list

• Size, thickness and cubic yards ordered, with any short-load fee.
• Grading and base material and depth; vapor barrier if the slab will sit under a heated space.
• Reinforcement, thickened edges and control joint spacing.
• Finish and sealer.
• Removal and haul-away of old concrete as its own line.
• Who contacts 811 and who handles any permit (ask your local building department whether you need one).

Questions to ask before you sign

1. What thickness is this price for, and why that thickness for my use?
2. “Can I get a line-item quote?” (from HomeGuide’s list)
3. Mesh, rebar or none, and what does each add?
4. How many yards are you ordering, and is there a short-load fee?
5. When can we drive on it? HomeGuide says to “Wait 1 to 2 weeks before driving on concrete.”

To get the cubic yards and each source’s price range for your own size, use the concrete cost calculator.

Have your own measurements? Run the concrete cost calculator — cubic yards, bags and a sourced price range for your size.

Illustrations here are AI-made sketches that show the idea. They are not photos of a real slab, driveway, product, job or person.

Sources

1. HomeGuide — How Much Does a Concrete Slab Cost? (2026) (written by Jennifer Carlson, dated Feb 3, 2026)
2. This Old House — How Much Does a Concrete Slab Cost? (2026 Prices) (updated Mar 17, 2026)
3. HomeGuide — How Much Does Concrete Cost Per Yard? (2026) (written by Tom Grupa, dated Jan 6, 2026)
4. Concrete Network (industry site) — Concrete Price Considerations: Cost of Concrete (updated July 14, 2026)
5. NRMCA — CIP 8, Discrepancies in Yield (rev. 2016), pp. 1–2
6. NRMCA — CIP 6, Joints in Concrete Slabs on Grade (rev. 2014), pp. 1–2
7. ICC — 2021 International Residential Code, Chapter 5 (R506 Concrete Floors (On Ground))
8. Common Ground Alliance — 811 Before You Dig (no update date shown; checked Nov 2, 2026)

Updated November 2, 2026