Estimate how much concrete you need and what a slab might cost, as a DIY project or with a contractor. Enter your local prices for the best estimate.
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| Item | Amount |
|---|---|
| Slab area | |
| Concrete needed | |
| Concrete cost | |
| Delivery fee | |
| Gravel base | |
| Rebar or mesh | |
| Forms, tools, misc | |
| DIY cost per sq ft | |
| Contractor estimate |
The calculator finds the volume of concrete for your slab, then adds up the main material costs using the prices you enter.
Concrete (cu yd) = length × width × thickness (in) ÷ 12 ÷ 27, plus extra
The default prices are rough placeholders, not current quotes. Concrete, gravel, and labor costs vary a lot by region and by season. Call a local ready-mix supplier and get quotes from two or three contractors, then enter your real numbers.
This tool does not include permits, excavation, sealing, control joints, or removal of existing material.
A 20 x 20 foot slab that is 4 inches thick needs about 4.94 cubic yards. With a 10 percent allowance, order about 5.4 cubic yards.
It depends on your area, the slab's size, thickness, and finish, and on whether you do the work yourself. DIY costs are mostly materials. Contractors price per square foot and include labor, prep, and finishing. Get local quotes and enter them above for an accurate figure.
Usually the materials cost less than a contractor's price, but pouring and finishing concrete is hard and time sensitive. Mistakes are costly, so many people hire out larger or visible slabs.
Four inches is typical for patios and walkways. Driveways and garage floors are often 5 to 6 inches or more. Follow local code and your slab's expected loads.
For small slabs under about 1 cubic yard, bags can work. For larger slabs, delivered ready-mix is usually faster and cheaper. Use the fence post concrete calculator to see how bag counts work.