Concrete slab cost: pads, patios and garage floors, by state
A 16 by 20 patio, 320 sq ft: about $2,550 to $3,750, typically $3,050. That's a 4 inch slab on grade, poured and finished in place, with the contractor's overhead, profit and sales tax. Everything in, it runs $7.75 to $11.75 a sq ft.
Anthony Hicks30+ years in construction. Updated November 5, 2026.
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What it costs
| Job | Cost |
|---|---|
| A 10 by 10 pad, 100 sq ft | $850 to $1,300 |
| A 16 by 20 patio, 320 sq ft | $2,550 to $3,750 |
| A 24 by 24 garage floor, 576 sq ft | $4,550 to $6,700 |
About $7.75 to $11.75 a sq ft, everything in.
Totals include the contractor's overhead and profit (20%) and the state's average sales tax. Prices as of November 2026.
What’s in these numbers
Each total is a typical job, priced the way a contractor’s estimate is priced:
- A 4 inch slab on grade, the usual thickness for patios, sheds, walks and garage floors. The residential code’s minimum for a concrete floor on the ground is 3 1/2 inches (IRC R506.1).
- Poured and finished in place: placed, leveled and finished on site.
- Overhead and profit: 20%, the standard markup on a contractor’s estimate.
- Sales tax on the materials, at the state’s average rate.
Not in them: tearing out an old slab, digging and grading, a gravel base, reinforcement, a vapor barrier, a pump truck, and decorative finishes like stamping or color. The epoxy flooring cost guide prices a coating on a finished floor, and the concrete driveway cost guide prices driveways.
What moves the price
- Thickness. A 6 inch slab takes half again as much concrete as a 4 inch one. The concrete calculator works out the yards for any thickness.
- Site work. Clearing, digging out, hauling soil and laying a compacted gravel base can cost as much as the pour on a rough site.
- Reinforcement. Wire mesh, fiber or rebar, and thickened edges for a garage or a building.
- Access. Where the truck can’t reach, the concrete is pumped or wheeled in, which adds labor or a pump.
- Small pours. Concrete trucks and crews have minimums, so a small pad costs more per square foot than a big slab.
- Where you live. Pick your state in the box above.
Working out your own slab
- Measure the length and width in feet and multiply for the square footage.
- Type it into the box above for the range at that size.
- Get the yards from the concrete calculator to see how much concrete it takes and whether bags or a truck make sense.
Common questions
How much does a 20 by 20 concrete slab cost?
About $3,100 to $4,700 for a 4 inch slab, 400 square feet poured and finished, before site work and reinforcement.
How much does a 24 by 24 garage slab cost?
About $4,550 to $6,700 for a 4 inch slab poured and finished, typically $5,400, before site work, reinforcement and a thickened edge.
What does a concrete slab cost per square foot?
$7.75 to $11.75 a sq ft for a 4 inch slab, poured and finished, with overhead, profit and sales tax included.
Is it cheaper to mix and pour your own?
For a small pad, the bags cost less than a contractor, but a slab of any size is heavy work that has to be placed and finished before it sets. The concrete calculator gives the bag count.
Does a 4 inch slab need rebar?
The residential code doesn’t call for reinforcement in a slab on the ground, but many contractors add wire mesh or fiber to control cracking, and a garage or a building on the slab often needs more. Local code and the engineer decide.