Updated June 17, 2026
Installed concrete slabs cost roughly $6 to $12 per square foot in 2025, which puts a 10 x 10 ft slab at $600 to $1,200 and a 20 x 20 ft slab at $2,400 to $4,800 installed with standard 4-inch thickness and wire-mesh reinforcement.
Cost by common slab size (installed)
| Slab size | Square feet | Low estimate | High estimate |
|---|---|---|---|
| 10 x 10 ft | 100 | $600 | $1,200 |
| 12 x 12 ft | 144 | $865 | $1,730 |
| 20 x 20 ft | 400 | $2,400 | $4,800 |
| 24 x 24 ft | 576 | $3,456 | $6,912 |
| 30 x 30 ft | 900 | $5,400 | $10,800 |
| 40 x 60 ft | 2,400 | $14,400 | $28,800 |
| 1,000 sq ft | 1,000 | $6,000 | $12,000 |
Use the Concrete Calculator to get the material volume first, then add contractor quotes for your area to check the total.
What drives the price up or down
- Thickness: going from 4 inches to 6 inches adds roughly 50 percent more concrete material.
- Reinforcement: rebar costs more than wire mesh but extends slab life, especially for driveways.
- Finishing: a broom finish is standard; stamped, exposed aggregate, or polished finishes add $2 to $8 per sq ft.
- Site prep: grading, gravel base, and form work are usually included in contractor quotes but verify.
- Region: labor rates vary widely; expect to pay more in coastal metros and less in rural areas.
How much does it cost to pour a 20 x 20 slab?
A 20 x 20 ft (400 sq ft) slab at 4 inches thick runs roughly $2,400 to $4,800 installed in most markets. Adding a 6-inch thickness for a garage or shop floor pushes material costs up by about 50 percent, so budget $3,000 to $6,000 or more depending on your contractor and local labor rates.
DIY vs hiring a contractor
A DIY pour on a small slab can cut costs by 40 to 60 percent if you already own or can rent a mixer and finishing tools. The material cost for concrete alone runs about $150 to $200 per cubic yard for ready-mix. Labor, grading, and forming typically account for half or more of the installed price. See concrete slab thickness to confirm your depth before ordering.
Cost breakdown: materials vs labor
For a typical installed slab, the cost breaks down roughly as follows. Concrete material (ready-mix) accounts for 25 to 35 percent of the total. Gravel sub-base accounts for 5 to 10 percent. Forms, rebar or mesh, and stakes make up another 5 to 10 percent. Labor for forming, pouring, screeding, finishing, and curing is the largest component at 40 to 55 percent of the total installed price. This is why DIY pours can save so much: you eliminate the single biggest cost line.
Concrete finishing options and their cost impact
| Finish type | Added cost per sq ft | Best for |
|---|---|---|
| Broom finish | Standard (no add) | Driveways, sidewalks, garage floors |
| Exposed aggregate | +$2 to $4 | Patios, pool decks, decorative |
| Stamped concrete | +$4 to $8 | Patios, driveways, decorative entries |
| Salt finish | +$1 to $2 | Pool surrounds, light texture |
| Polished / ground | +$3 to $10 | Interior garage floors, commercial |
Getting an accurate quote from a contractor
When you solicit bids, specify the exact square footage, thickness, reinforcement type (rebar size and spacing, or wire mesh gauge), and finish. Ask whether the quote includes excavation and gravel base, form work, finishing, and cleanup. A detailed scope prevents surprise change orders. Get at least three quotes for jobs over $1,500, and check references for pours over 500 square feet because concrete finishing on large slabs requires experience and a good crew to keep up with the setting time.
When to add expansion joints and why they affect cost
Expansion joints (or isolation joints) separate the new slab from existing structures like house foundations, step footings, or adjacent slabs. They are usually a fiber expansion strip inserted before the pour. Most contractors include them in their base bid, but verify. For larger pours (over 400 square feet), saw-cut control joints at 8 to 12 foot intervals are standard and add a small labor charge, usually $0.25 to $0.75 per linear foot of saw cut. These joints matter for long-term appearance; skipping them almost guarantees visible random cracking within a few years.
Permits and inspections and how they affect your budget
Many jurisdictions require a building permit for concrete work that exceeds a certain size or is attached to a dwelling. Permit costs vary widely: a simple patio slab may cost $50 to $150 in permit fees, while a foundation slab often requires plan review and an inspection fee that can run $200 to $500 or more. Always check with your local building department before starting. Unpermitted work can affect homeowner's insurance claims and home resale. Budget the permit fee as a line item and add one to two weeks for permit processing time in your project schedule.
How to estimate material cost separately from installed cost
If you are planning a DIY pour, the material budget breaks down as follows. For a 20 x 20 ft slab at 4 inches: you need roughly 5 cubic yards of ready-mix at $150 to $200 per yard, or $750 to $1,000 for the concrete alone. Add 1.5 to 2 cubic yards of compacted gravel at $35 to $50 per yard delivered, or $55 to $100. Wire mesh or rebar for a 400 sq ft slab adds $100 to $250 depending on the reinforcement spec. Forming lumber (2 x 4s at 8 feet) for the perimeter adds $40 to $80. Curing compound or plastic sheeting adds $20 to $40. Total DIY material cost for a 20 x 20 slab: roughly $1,000 to $1,500. Compare that to the installed contractor price of $2,400 to $4,800 and you can see where the labor value lies. Use the Concrete Calculator to confirm your material volumes before pricing out each line item.