Free Tool
Concrete Calculator
Enter your slab dimensions and thickness to estimate cubic yards of ready-mix, bag count for smaller pours, and a rebar grid for a patio, footing, or pad.
FAQ
Frequently Asked Questions
How much concrete do I need for a slab?
Multiply length x width x thickness (converted to feet) to get cubic feet, then divide by 27 to get cubic yards — that's the number ready-mix suppliers quote by. Always add a waste factor; concrete that runs short mid-pour is a real problem since a slab should be poured continuously.
Should I use bagged concrete or order ready-mix?
Bagged mix is fine for small pours like footings or post holes — under about 1 cubic yard. Beyond that, ready-mix delivered by truck is far more practical and gives more consistent strength than mixing dozens of bags by hand.
How thick should a concrete patio or driveway be?
4 in. is standard for patios, walkways, and other foot-traffic-only slabs. Driveways and anywhere vehicles will drive or park need 5-6 in., often with reinforcement, especially on our region's expansive and caliche-heavy soils.
Do I need rebar or wire mesh in a concrete slab?
Generally yes in the Las Vegas Valley — reinforcement helps control cracking from our soil movement and large day-to-night temperature swings. A common rule of thumb is a rebar grid on roughly 24 in. centers in both directions for residential slabs.
Is this calculator accurate enough to order concrete from?
It's a solid planning estimate for budgeting, not a final order — actual yardage should always be confirmed with your ready-mix supplier, who will also account for slab thickness variation and site access. Our design process includes precise take-offs for any concrete work tied to a project we design.
Want an exact material plan for your yard?
This calculator gives you a solid planning estimate. Our design process includes a precise material take-off for your actual site — so you have a real baseline to compare contractor bids against.
Book a 3D Design Consultation