Calculate the exact amount of concrete needed for slabs, footings, columns, walls, and tubes with bag and cost estimates
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Planning a concrete project? Our concrete calculator helps you determine the precise amount of concrete needed for any shape—slabs, footings, columns, walls, or tubes. Get accurate volume estimates in cubic yards or meters, know how many bags you'll need, and see cost projections before you start.
Concrete is measured in cubic yards (US) or cubic meters (metric). The volume depends on the shape of your project. For slabs and footings, it's length × width × depth. For columns and tubes, we use π × radius² × height. Our calculator accounts for waste (typically 10%) and recommends whether to use bags or order ready-mix based on project size.
Volume Calculation Formula
V = L × W × D (slab) or V = π × r² × h (column)Calculate concrete for backyard patios, walkways, and garden paths.
Determine concrete needed for post holes and fence foundations.
Estimate concrete for footings, stem walls, and small foundations.
Create accurate material quotes for concrete work and avoid over-ordering.
It depends on the bag size: 80 lb bags yield about 0.6 cubic feet, 60 lb bags about 0.45 cubic feet, and 40 lb bags about 0.3 cubic feet. Our calculator shows all three options. For projects over 1 cubic yard, consider ready-mix delivery.
For projects under 1/2 cubic yard, bags are practical. For 1/2 to 1 cubic yard, it depends on your preference. Over 1 cubic yard, ready-mix is usually more economical and efficient, with better quality control.
Standard sidewalks and patios: 4 inches. Driveways: 4-6 inches. Garage floors: 4 inches minimum, 6 inches for heavy vehicles. Footings: typically 8-12 inches, check local building codes.
10% extra accounts for spillage, uneven ground, form imperfections, and leftover concrete in the mixer. It's better to have slightly more than to run short mid-pour, as cold joints weaken the concrete.
80 lb bags cost $5-8 each (about $100-130 per cubic yard). Ready-mix delivery ranges from $125-175 per cubic yard with typical minimum orders of 1-2 yards. There's usually a short load fee for less than full trucks.