How the price is calculated
Poured concrete is priced by the square foot: a starting price that covers the smallest job (the truck, the forms, the crew showing up), plus a rate for every square foot above it. The calculator uses typical rates for a licensed, insured contractor, 4 inches thick with wire mesh:
- Patio or slab: $1,200 for the first 100 square feet, then $8 a square foot. A 10 by 10 slab is $1,200, a 12 by 12 is $1,552, a 20 by 20 is $3,600
- Concrete driveway: $2,400 for the first 200 square feet, then $9 a square foot. A 600 square foot driveway is about $6,000
- Sidewalk or walkway: $750 for the first 50 square feet, then $9 a square foot. A 4 by 30 walk is $1,380
- Stamped or decorative: $1,800 for the first 100 square feet, then $14 a square foot, one color and the first seal coat included. A 300 square foot stamped patio is about $4,600
- Repair or resurfacing: $600 for the first 100 square feet, then $4 a square foot
Add-ons go on top: tearing out and hauling off old concrete ($900 on a patio, $1,500 on a driveway), rebar instead of wire mesh, a 6-inch pour for a shed, RV or heavy truck, sealer and integral color. Prices run higher in big metros and lower in rural counties. Read how much to charge for concrete per square foot for the method behind the numbers.
How much concrete you need (the slab estimator part)
Cubic yards = length x width x thickness in feet, divided by 27. At 4 inches thick, one cubic yard covers about 81 square feet; at 6 inches, about 54. A 20 by 20 slab at 4 inches is 4.9 cubic yards, so most contractors order 5.5 to cover the base and spillage. Small orders often carry a short-load fee from the ready-mix plant, one reason small slabs cost more per square foot.
Measuring the slab
Trace only the area that gets poured. For a patio, outline it against the house; for a driveway, from the garage to the street, with the apron as part of it. Satellite images can be a year or two old and trees hide edges, so the price is a range and the contractor measures again on site.
For concrete contractors
The same calculator goes on your website with your starting prices, rates and add-ons. Homeowners see your range at 9 p.m., and the leads that reach you come with the address and the measured square feet.