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Concrete Slab Cost Calculator - Materials & Labor (2026)

Free concrete slab cost calculator. Enter your slab size, thickness, and finish to estimate concrete, gravel base, reinforcement, and labor costs in seconds.

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Common slab sizes

e.g. 20

e.g. 20

or

Concrete Slab Cost Estimate

Slab Size400.00 sq ft (20x20)
Concrete Needed5.4 cu yd (with 10% waste)

Cost Breakdown

Concrete (ready-mix)$706 - $1,032
Place & Finish (broom finish (standard))$1,200 - $2,400
Gravel Base$600 - $1,200
Wire Mesh$140 - $260

Estimated Total Cost

$2,646 - $4,892

20x20 ft, 4" slab ($7-$12/sf installed)

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How Much Does a Concrete Slab Cost?

Last updated: 2026-09-24

A concrete slab costs $6-$13 per square foot installed for a typical residential project. That price covers the ready-mix concrete at $130-$190 per cubic yard, a compacted gravel base, wire mesh or rebar, and the labor to form, pour, and finish the slab. A plain 4-inch broom finish is cheapest. Thicker pours, a rebar grid, and decorative finishes push the cost up. In the Pacific Northwest, wet or soft subgrade is common. If the soil won't compact, you may need to over-excavate and bring in extra gravel, and that has to be priced before you quote. Always walk the site before you quote a slab.

Concrete Slab Cost by Size and Thickness

Installed prices with a broom finish, compacted gravel base, and 10% concrete waste: wire mesh in the 4-inch column, rebar grid in the 6-inch column. National figures before regional adjustment. Removal, pumping, short-load fees, and decorative finishes are extra.

Slab Size Area 4 inch 6 inch
10x10 (shed pad)100 sq ft$660-$1,220$800-$1,440
12x16 (patio)192 sq ft$1,270-$2,350$1,530-$2,760
20x20 (patio/garage)400 sq ft$2,650-$4,890$3,180-$5,750
24x24 (shop/garage)576 sq ft$3,810-$7,050$4,580-$8,280
24x40 (shop floor)960 sq ft$6,350-$11,740$7,630-$13,800

Highlighted row = most common small project. Add $2-$6/sf to remove an existing slab first. The calculator's 20x20 garage preset above defaults to a 5-inch slab, between the 4-inch and 6-inch columns shown here; run it directly for a 5-inch estimate.

What Each Part of a Slab Costs

Breaking the slab into line items shows where the money goes and where you can adjust the bid.

Line Item Typical Cost Notes
Ready-mix concrete$130-$190/cu ydDelivered, 3,000-4,000 PSI
Gravel base$1.50-$3/sfCompacted; skip only on well-drained, compacted subgrade
Wire mesh$0.35-$0.65/sfLight reinforcement for patios (see Sources)
Rebar grid$0.80-$1.50/sfLoad-bearing slabs, driveways
Place and finish labor$3-$16/sfBroom cheapest, stamped priciest
Old slab removal$2-$6/sfPlus dump fee, varies by thickness

Most ready-mix plants add a short-load fee when you order less than their minimum. The minimum and the fee vary by plant (often charged per yard below the minimum), so get your plant's number and build it into the bid.

Concrete Slab Cost & Installation Guide

Pricing by size and thickness, what each line item costs, how to calculate cubic yards, and what to know before you pour.

How Much Does a Concrete Slab Cost in 2026?

A concrete slab costs $6-$13 per square foot installed for most residential projects. That covers the ready-mix concrete, the gravel base, reinforcement, and the labor to form, pour, and finish it. A plain 4-inch slab sits at the low end. Thicker pours, rebar, and decorative finishes push the high end.

  • 10x10 shed pad (4 inch, wire mesh): $660-$1,220 installed
  • 12x16 patio (4 inch, wire mesh): $1,270-$2,350 installed
  • 20x20 garage slab (5 inch, wire mesh): $2,820-$5,150 installed
  • 24x40 shop floor (6 inch, rebar grid): $7,630-$13,800 installed

The ready-mix concrete itself runs $130-$190 per cubic yard delivered as of 2026, and most plants add a short-load fee when you order less than their minimum (the minimum and the fee vary by plant). Prices vary by region, so verify local rates before you bid.

Key Takeaways

  • Standard installed range: $6-$13 per sq ft
  • Ready-mix concrete: $130-$190 per cubic yard delivered
  • Most plants add a short-load fee below their order minimum

What Drives Concrete Slab Cost Up or Down?

Thickness, finish, and reinforcement are the three biggest cost drivers, but site work can swing a bid more than any of them.

  • Thickness: A 6-inch slab uses 50% more concrete than a 4-inch slab of the same size. Step up thickness for driveways, shops, and anything that carries vehicles.
  • Finish: A broom finish adds $3-$6/sf in labor. Stamped or decorative work jumps to $9-$16/sf.
  • Reinforcement: Wire mesh runs about $0.35-$0.65/sf. A rebar grid runs $0.80-$1.50/sf and is worth it on anything load-bearing.
  • Gravel base: A compacted gravel base adds $1.50-$3/sf. On soft or poorly drained soil, skipping it is a common way to crack a slab.
  • Demolition: Removing and hauling an old slab adds $2-$6/sf depending on thickness and access.
  • Access and pumping: A concrete pump adds cost when the truck cannot reach the pour. Get a quote before you bid.

Key Takeaways

  • A 6-inch slab uses 50% more concrete than a 4-inch slab
  • Gravel base ($1.50-$3/sf) matters most on soft or poorly drained soil
  • A concrete pump adds cost when the truck cannot reach the pour

How Much Concrete Do You Need for a Slab?

Concrete is ordered in cubic yards. To find yards, multiply length by width by thickness in feet, then divide by 27. Add 10% for waste, spillage, and uneven subgrade.

  • Formula: (length ft x width ft x thickness ft) / 27 = cubic yards
  • 4-inch slab: a 20x20 area needs about 5.4 cubic yards with waste
  • 6-inch slab: the same 20x20 area needs about 8.1 cubic yards with waste

Round your order up to the next quarter yard rather than down. Coming up short means waiting on a second truck and risking a cold joint in the pour. For exact takeoffs, run the numbers through our concrete tools before you call the plant.

Key Takeaways

  • Cubic yards = (L x W x thickness in feet) / 27
  • Add 10% for waste and uneven subgrade
  • Order to the next quarter yard to avoid coming up short

Concrete Slab Labor Cost: What Contractors Charge

Labor to place and finish a slab runs $3-$16 per square foot depending on the finish. Most concrete crews bid the slab as a unit price, not by the hour.

  • Broom finish: $3-$6/sf (standard, slip-resistant, most common)
  • Smooth steel-trowel: $4-$7/sf (interior floors, garages)
  • Integral color: $6-$10/sf (color mixed into the concrete)
  • Exposed aggregate: $7-$12/sf (decorative, hides wear)
  • Stamped: $9-$16/sf (patterns and texture, slowest to install)

The prep, the forming, and the gravel work usually take longer than the pour itself.

Key Takeaways

  • Place and finish labor: $3-$16/sf by finish type
  • Broom finish is the standard at $3-$6/sf
  • Forming and base prep take longer than the pour

Common Concrete Slab Cost Mistakes

Skipping the base and underestimating site prep are two mistakes that wreck slab budgets. A slab is only as good as what sits under it.

  • Pouring on dirt. A slab poured on soft or poorly drained soil without a compacted gravel base is far more likely to crack and settle. The base is $1.50-$3/sf and it is cheap insurance on the job.
  • Forgetting control joints. Concrete cracks. Control joints decide where. Cutting them within 24 hours keeps random cracks out of the finished surface.
  • Underbidding small pours. Most ready-mix plants add a short-load fee when you order less than their minimum. The minimum and the fee vary by plant, so get your plant's number and build it into the bid.
  • Ignoring access. If the mixer cannot back up to the forms, you are renting a pump or wheelbarrowing yards by hand. Walk the site before you quote.
  • Not budgeting for removal. Tearing out an old slab adds $2-$6/sf and a dump fee. Homeowners almost never account for it.

Key Takeaways

  • A compacted gravel base helps prevent cracking and settling, especially on soft soil
  • Cut control joints within 24 hours to control cracking
  • Short-load fees vary by plant; get your plant's number before you bid

Common Slab Mistakes That Cost Money

  • Pouring on dirt instead of a gravel base. A slab poured on soft or poorly drained soil without a compacted gravel base is far more likely to crack and settle. The base is $1.50-$3/sf and it is cheap insurance on the job.
  • Forgetting control joints. Concrete cracks, period. Control joints decide where it cracks. Cut them within 24 hours of the pour and you keep random cracks out of the finished surface.
  • Underbidding small pours. Most ready-mix plants add a short-load fee when you order less than their minimum. The minimum and the fee vary by plant, so get your plant's number and build it into the bid.
  • Not checking truck access. If the mixer cannot back up to the forms, you are paying for a pump or wheelbarrowing yards by hand. Get a pump quote before you bid.
  • Skipping rebar on load-bearing slabs. Wire mesh is fine for a patio. A driveway or shop floor carrying vehicles needs a rebar grid. The upgrade is under $1/sf, and it holds cracks tight under vehicle loads.

Sources

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How to Use This Calculator

Enter Your Slab Dimensions

Input the length and width of the slab in feet, or tap a common size preset. The calculator works for any rectangular slab from a small shed pad to a full shop floor.

Choose the Thickness

Pick 4 inches for patios and walkways, 5 inches for garages, or 6 inches for driveways and shops. Thickness drives how many cubic yards of concrete you need.

Select Finish and Reinforcement

Choose a broom, smooth, colored, exposed aggregate, or stamped finish, then add wire mesh or a rebar grid. Each option adjusts the labor and material cost per square foot.

Add Base and Removal

Include a compacted gravel base if you are pouring on bare soil, and check old slab removal if you are tearing out existing concrete first. Enter your state for regional pricing.

Concrete Slab Cost Formulas

Area = Length x Width
Concrete (cu yd) = Area x (Thickness / 12) / 27 x 1.10
Concrete Cost = Cubic Yards x $130-$190/yd
Labor = Area x finish rate ($3-$16/sf)
Base = Area x $1.50-$3/sf (if gravel base)
Reinforcement = Area x mesh/rebar rate
Removal = Area x $2-$6/sf (if removing old slab)
Total = Concrete + Labor + Base + Reinforcement + Removal

Where:

Thickness
= 4 in (patios), 5 in (garages), 6 in (driveways and shops)
Finish
= Broom $3-$6/sf, smooth $4-$7/sf, colored $6-$10/sf, exposed $7-$12/sf, stamped $9-$16/sf
Reinforcement
= Wire mesh $0.35-$0.65/sf, rebar grid $0.80-$1.50/sf
Waste
= 10% added to concrete volume for spillage and uneven subgrade

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Frequently Asked Questions

How much does a concrete slab cost per square foot?

A concrete slab costs $6-$13 per square foot installed in 2026, including the ready-mix concrete, gravel base, reinforcement, and the labor to form, pour, and finish it. A plain 4-inch broom-finished slab sits at the low end. A 6-inch slab with rebar and a stamped finish runs about $14-$24 per square foot, above that range. The concrete alone is $130-$190 per cubic yard delivered.

How much does a 20x20 concrete slab cost?

A 20x20 concrete slab (400 sq ft) costs $2,650-$5,750 installed with a broom finish, from a 4-inch slab with wire mesh at the low end to a 6-inch slab with rebar at the high end. A stamped finish pushes it to roughly $5,050-$9,750. Step up to a 5-inch slab for a garage and you add roughly 25% to the concrete. That size needs about 5.4 cubic yards of concrete at 4 inches thick.

Is a gravel base really necessary under a slab?

In most cases, yes. A compacted gravel base gives the concrete a stable, draining surface that resists cracking and settling, especially on soft or poorly drained soil. It costs $1.50-$3 per square foot. The base is cheap insurance on the job, and skipping it on bad soil often means paying for it twice.

How do contractors price a concrete slab for a client?

Most concrete contractors price a slab as a unit price per square foot, then break it into line items: concrete, gravel base, reinforcement, forming, and finishing. They calculate the cubic yards with our concrete calculator, add 10% for waste, mark up materials 15-30%, and add a short-load fee on small pours. A clean bid lists each item so the homeowner can see exactly what drives the price. Try EstimationPro free (3 estimates, no credit card) to turn your slab numbers into a line-item bid. Contractors save 2+ hours per estimate.

How thick should a concrete slab be?

Four inches is standard for patios, sheds, and walkways. Go to five inches for a garage that holds a car, and six inches for driveways, shops, or anything carrying heavy vehicles. A 6-inch slab uses 50% more concrete than a 4-inch slab of the same size, so thickness has a real cost impact. For load-bearing slabs, always add a rebar grid instead of wire mesh.

How much concrete do I need for a slab?

Multiply length by width by thickness in feet, then divide by 27 to get cubic yards. Add 10% for waste. A 20x20 slab at 4 inches needs about 5.4 cubic yards. The same slab at 6 inches needs about 8.1 cubic yards. Run an exact takeoff with our concrete volume calculator before you call the ready-mix plant.

Does the price include removing an old slab?

No, removal is extra. Tearing out and hauling an old slab adds $2-$6 per square foot plus a dump fee, depending on thickness and access. A 4-inch slab is faster to break out than a 6-inch reinforced one. Homeowners almost never budget for demolition, so it is worth calling out as its own line item on the estimate.

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