Concrete Calculator

Step 1: Select shape: Slab, Column, or Wall.

Step 2: Enter dimensions. Depth/thickness in inches, other dimensions in feet.

Step 3: Set quantity for multiple identical shapes.

Step 4: Click Calculate for cubic yards and bag estimates.

Concrete is sold by cubic yard (27 cu ft). One cubic yard covers about 81 sq ft at 4 inches thick. Pre-mixed bags for small jobs; ready-mix trucks for 2+ cubic yards.

Common thickness: 4 inches patios, 6 inches driveways, 8-12 inches footings. Always add 5-10% extra for waste.

Slab: L(ft) x W(ft) x D(in)/12 / 27 = cu yd
Example: 20x10x4in = 66.67 cuft = 2.47 cu yd

Column: pi x (D/2)^2 x H / 27

Bags: 40lb=0.011, 60lb=0.017, 80lb=0.022 cu yd each

Example 1: 12x12ft patio, 4in = 1.78 cu yd (81 bags of 80lb)

Example 2: 4 round footings, 1.5ft diam, 3ft deep = 0.79 cu yd

Example 3: Wall 20x3ft, 8in thick = 1.48 cu yd

Order 5-10% extra. Ground is never perfectly level.

Depth in INCHES, not feet. 4 inches, not 4 feet!

Round up to nearest half-yard for truck delivery.

Check truck access. Chute reach is about 18 feet.