A concrete slab costs about $5 to $8 per square foot installed in 2026, or $2,200 to $3,100 for a 20 x 20 slab. Enter your slab size below to get an itemized estimate, the cubic yards or bags of concrete you need, and a side-by-side look at DIY vs. hiring a pro.
Concrete Slab Cost Calculator
Cost breakdown
| Item | Materials | Labor | Total |
|---|---|---|---|
| Total | $0 |
Pro vs. DIY
| Option | Total | Per sq ft |
|---|
How Much Does a Concrete Slab Cost in 2026?
A professionally installed 4-inch concrete slab costs about $5 to $8 per square foot in 2026, or roughly $2,200 to $3,100 for a 20 x 20 slab. That price includes site prep, a gravel base, forms, ready-mix concrete, wire mesh and a broom finish. A garage floor with rebar, a vapor barrier and thickened edges runs closer to $9 to $12 per square foot. Doing it yourself with a ready-mix truck can cut the cost by 40% or more.
Concrete Slab Cost by Size
| Slab size | Square feet | Concrete to order | Professional install | DIY with ready-mix |
|---|---|---|---|---|
| 10 x 10 ft | 100 | 1.5 cu yd | $850 – $1,200 | About $650 |
| 10 x 12 ft | 120 | 1.75 cu yd | $850 – $1,200 | About $710 |
| 12 x 12 ft | 144 | 2 cu yd | $930 – $1,320 | About $770 |
| 12 x 16 ft | 192 | 2.75 cu yd | $1,190 – $1,680 | About $920 |
| 16 x 20 ft | 320 | 4.5 cu yd | $1,840 – $2,590 | About $1,300 |
| 20 x 20 ft | 400 | 5.5 cu yd | $2,170 – $3,070 | About $1,460 |
| 20 x 24 ft | 480 | 6.75 cu yd | $2,590 – $3,660 | About $1,720 |
| 24 x 24 ft | 576 | 8 cu yd | $3,060 – $4,320 | About $1,980 |
| 24 x 30 ft | 720 | 10 cu yd | $3,780 – $5,340 | About $2,410 |
| 30 x 30 ft | 900 | 12.25 cu yd | $4,730 – $6,670 | About $2,990 |
| 30 x 40 ft | 1,200 | 16.5 cu yd | $6,230 – $8,790 | About $3,880 |
Small slabs cost more per square foot because most contractors charge a minimum of around $1,000, and ready-mix suppliers add short-load fees for orders under about 5 cubic yards.
Cost by Project
| Project | Typical size and specs | Estimated cost |
|---|---|---|
| Shed pad | 10 x 12 ft, 4 in, wire mesh | About $1,000 |
| Patio | 12 x 16 ft, 4 in, wire mesh | About $1,400 |
| Parking pad | 10 x 20 ft, 4 in, 4,000 psi | About $1,500 |
| One-car garage floor | 12 x 24 ft, rebar, vapor barrier, thickened edges | About $3,450 |
| Two-car garage floor | 24 x 24 ft, rebar, vapor barrier, thickened edges | $5,160 – $7,280 |
| RV pad | 12 x 40 ft, 6 in, rebar, thickened edges | About $5,750 |
What Affects the Cost of a Concrete Slab?
Thickness
Every extra inch adds about 25% more concrete. A 4-inch slab is standard for patios, sheds and garage floors. Use 5 to 6 inches for driveways and parking pads that see trucks, and 6 inches or more for RVs, boats and heavy equipment.
| Thickness (20 x 20 slab) | Concrete needed | Installed cost | Per sq ft |
|---|---|---|---|
| 4 inches | 4.9 cu yd | $2,560 | $6.40 |
| 5 inches | 6.2 cu yd | $2,860 | $7.14 |
| 6 inches | 7.4 cu yd | $3,120 | $7.79 |
| 8 inches | 9.9 cu yd | $3,780 | $9.44 |
Concrete Prices
Ready-mix concrete averages about $145 per cubic yard for standard 3,000 psi mix and about $165 for 4,000 psi, which is recommended for garage floors and driveways. Expect a delivery fee of roughly $75 to $150 per truck, plus a short-load fee of $40 to $80 when you order less than about 5 yards. Fiber mesh adds about $8 to $15 per yard. Bagged concrete costs about $6 to $8 per 80 lb bag, and it takes about 45 bags to make one cubic yard.
Reinforcement
- Fiber mesh: mixed into the concrete. Helps control surface cracking for about $8 to $15 per yard.
- Welded wire mesh: about $0.35 to $0.50 per square foot installed. A good choice for patios, walkways and shed pads.
- Rebar grid: about $2 to $3 per square foot installed. Recommended for garage floors, driveways and anything carrying vehicles.
Finish
| Finish | Added cost per sq ft | 20 x 20 slab total |
|---|---|---|
| Broom finish (standard) | Included | $2,560 |
| Smooth trowel | About $0.75 | $2,860 |
| Exposed aggregate | About $4 | $4,160 |
| Colored or stained | $3.50 – $7.50 | $4,560 |
| Stamped | $10 – $14 | $7,360 |
Site Prep and Extras
- Grading and excavation: about $0.40 per square foot on a flat site, rising to $3 or more on a slope.
- Removing an old slab: about $3 per square foot, including hauling.
- Vapor barrier: about $0.50 per square foot. Needed under garage floors and any slab that will be enclosed.
- Thickened edges: a built-in footing around the edge of the slab, common for garages and sheds, for about $1 per square foot of slab.
- Pump truck: often $500 to $1,000 when the ready-mix truck can’t reach the pour site.
- Location: the same 20 x 20 slab costs about $2,290 in a low-cost rural area and about $3,230 in a high-cost metro.
How Much Concrete Do You Need?
To figure out how much concrete to order, multiply length x width x thickness (all in feet), then divide by 27 to get cubic yards. Add about 10% for uneven ground and spillage.
Example: a 20 x 20 slab at 4 inches thick is 20 x 20 x 0.33 = 133 cubic feet. Divide by 27 and you get 4.9 cubic yards, so order about 5.5 yards with the extra.
- One cubic yard covers about 81 sq ft at 4 inches, 65 sq ft at 5 inches, or 54 sq ft at 6 inches.
- An 80 lb bag makes about 0.6 cubic feet, so you need about 45 bags per cubic yard.
- A 60 lb bag makes about 0.45 cubic feet, or about 60 bags per cubic yard.
Bags vs. Ready-Mix vs. Hiring a Pro
Bagged concrete makes sense for small jobs under about 1 cubic yard, like a pad for an AC unit or a few fence posts. Beyond that, the number of bags gets overwhelming. A 10 x 12 shed pad needs about 74 bags, which is nearly 3 tons to mix by hand.
DIY with ready-mix is the biggest money saver for slabs between about 100 and 400 square feet, if you have experience and at least three or four helpers. Concrete sets fast, so forms, base, reinforcement and tools all need to be ready before the truck arrives.
Hiring a contractor is the best choice for garage floors, driveways, large slabs and decorative finishes. A good crew delivers a flatter, stronger slab with proper joints, and mistakes in concrete are expensive to fix. Use the calculator above to compare all three options for your slab.
Get Quotes from Local Concrete Contractors
Get at least three written quotes, and make sure each one lists the thickness, concrete strength, reinforcement, base depth and finish so you can compare them fairly.
Tips to Save Money on a Concrete Slab
- Combine projects. Pouring a patio and a walkway the same day spreads the delivery fee and contractor minimum across more concrete.
- Do the prep yourself. Clearing, grading and spreading the gravel base are labor-heavy but forgiving tasks.
- Stick with a broom finish. Decorative finishes can double or triple the price.
- Schedule in spring or fall. Mild weather means better curing, and you avoid the summer rush and winter heating costs.
- Don’t skimp on the base or reinforcement. Fixing a cracked or sunken slab costs far more than doing it right the first time.
Planning a Garage?
The slab is just one part of a garage budget. Our garage cost calculator prices the whole building, including the foundation, framing, roof, doors and electrical. See our guide to garage foundation types to choose between a slab, piers or a raised floor, and price a matching concrete driveway. Planning to coat the new floor? Try our garage floor epoxy calculator.
Frequently Asked Questions
How much does a 20 x 20 concrete slab cost?
About $2,200 to $3,100 installed for a standard 4-inch slab with wire mesh and a broom finish. Adding rebar, a vapor barrier and thickened edges for a garage floor raises it to roughly $3,800 to $5,400. Doing it yourself with ready-mix costs about $1,500 in materials and rentals.
How thick should a concrete slab be?
Four inches is standard for patios, walkways, sheds and garage floors for cars. Use 5 to 6 inches for driveways with heavy trucks and 6 inches or more for RVs and equipment. Check your local building code for garage and foundation requirements.
Is it cheaper to pour your own concrete slab?
Yes. Labor is usually 40% to 50% of the cost, so a DIY pour with ready-mix can save that much. The trade-off is risk: concrete gives you one chance, and a poorly finished slab can’t be easily fixed. DIY works best for small, simple slabs.
Do I need rebar in a concrete slab?
Rebar is recommended for garage floors, driveways and any slab that carries vehicles. Wire mesh or fiber is usually enough for patios, walkways and shed pads. Reinforcement doesn’t stop cracks from forming, but it keeps them tight and prevents the slab from separating.
Do I need a permit for a concrete slab?
Garage and building foundations almost always need a permit. Many towns don’t require one for a patio or small shed pad, but rules vary, especially for slabs near property lines or that change drainage. Call your local building department before you pour.
How long does a concrete slab take to cure?
You can usually walk on a new slab after 24 to 48 hours and drive a car on it after about 7 days. Concrete reaches most of its design strength in about 28 days. Keep it moist for the first week, especially in hot or windy weather, to reduce cracking.
Pricing last updated October 2026 using national-average material and labor costs. Concrete prices vary by supplier, region and season; always get written quotes before you order or hire.
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