Concrete Calculator

Multiply length × width × thickness. For a 10ft × 12ft slab that's 4 inches thick: 10 × 12 × 0.33 = 39.6 cubic feet (1.1 cubic yards). Always add 5-10% extra for waste and spillage.

The most common mix ratio is 1:2:3 (cement:sand:aggregate by volume) for general construction. For heavy-duty applications, use 1:1.5:3. The calculator adjusts material quantities based on your chosen mix ratio and total volume.

An 80 lb bag covers about 0.6 cubic feet. For 1 cubic yard (27 cubic feet), you need approximately 45 bags. The calculator automatically converts your volume to bag count based on the bag size you select.

Yes, always add 5-10% for forms, spillage, and uneven ground. For complex shapes or remote pours, add 10-15%. The calculator includes a wastage factor setting to account for this automatically.

Use the formula V = πr²h (pi × radius squared × height). For a 12-inch diameter column that's 8 feet tall: π × 0.5² × 8 = 6.28 cubic feet. The calculator handles cylindrical shapes automatically.

One cubic yard equals 27 cubic feet. Ready-mix concrete is typically ordered in cubic yards, while bag quantities are based on cubic feet. The calculator converts between units automatically.