Concrete Volume Calculator

1. Select the shape. Choose slab/footing for flat pours, wall for vertical pours, or column for round forms like sonotubes.

2. Enter dimensions. For slabs, enter length, width, and thickness. For columns, enter diameter and height. Measurements should be in feet for length/width and inches for depth/diameter.

3. Set quantity and waste. If you are pouring multiple identical forms, set the quantity. Use 10% waste for standard pours, 15% for complex shapes or first-time pours.

4. Enter your local cost. Ready-mix prices vary by region. Call your local batch plant for current pricing. The calculator defaults to $150/CY as a national average.

The calculator converts all measurements to cubic feet, then divides by 27 to get cubic yards (since 1 CY = 27 cubic feet).

For a standard 4-inch slab, there is a handy shortcut: divide the square footage by 81 to get cubic yards. This works because (1/3 foot depth x 1 sqft) / 27 = 1/81.

Weight is estimated at approximately 3,700 lbs per cubic yard (1.85 tons), which is the standard density for normal-weight concrete. Bag count is based on 80-lb bags yielding approximately 0.6 cubic feet each.