Construction Calculator
Concrete Mix
Estimate mix for forms, footings, and post holes
Most concrete mix provides approximately 0.0075 cubic feet of volume per pound. A 60-pound bag yields about 0.45 cubic feet and an 80-pound bag about 0.60 cubic feet.
Rectangular Forms
Cuboid volume
Use this calculator for rectangular containers, forms, and footings. Enter measurements in inches.
Round Forms
Cylinder volume
Use this calculator for cylindrical forms and post-hole foundations. Enter measurements in inches.
Common Example
Post-hole foundation
A common post-hole foundation is 12 inches in diameter, or 6 inches in radius, and 18 inches deep. It needs about 1.18 cubic feet of mix: roughly two 80-pound bags or 2.6 sixty-pound bags.
