How to Use

1
Select the shape: slab/footing for flat pours, wall for vertical pours, or column for round forms
2
Choose imperial (feet/inches) or metric (meters/centimeters) units
3
Enter the dimensions and click Calculate to see cubic yards/meters and bag estimates

Formula

Volume = Length × Width × Depth

For slabs and footings, volume is calculated as length × width × depth, then converted to cubic yards (÷ 27 from cubic feet) or cubic meters. For columns, the formula uses π × r² × height.

Column Volume = π × (diameter / 2)² × height

Examples

10 × 10 ft patio slab, 4 inches deep

10 × 10 × (4/12) = 33.33 cu ft ÷ 27 = 1.23 cubic yards

Result: 1.23 cubic yards (~56 bags at 60 lb)

Driveway: 20 × 12 ft, 6 inches deep

20 × 12 × (6/12) = 120 cu ft ÷ 27 = 4.44 cubic yards

Result: 4.44 cubic yards (~200 bags at 60 lb)

Column: 12-inch diameter, 3 ft tall

π × 0.5² × 3 = 2.36 cu ft ÷ 27 = 0.09 cubic yards

Result: 0.09 cubic yards (~4 bags at 60 lb)

FAQ

Order 5-10% more than calculated to account for spillage, uneven subgrade, and form irregularities.

For jobs under 1 cubic yard, pre-mixed bags are practical. For anything over 1-2 cubic yards, a ready-mix delivery truck is more cost-effective and easier to work with.

A standard residential slab is 4 inches thick. Driveways and garage floors are typically 5-6 inches. Footings are often 8-12 inches or more depending on load requirements.