Footing calculator

12 in by 48 in tube: 3.14 cu ft, 6 bags of 80 lb.

Job sheet

Plumb footing job sheet

12 in tube, 48 in of concrete.

  • Volume3.14 cu ft0.116 cu yd.
  • 80 lb bags6QUIKRETE 1101 yield 0.6 cu ft. No waste in this count.
Plumb footing job sheet
12 in tube, 48 in of concrete.

Volume: 3.14 cu ft (0.116 cu yd.)
80 lb bags: 6 (QUIKRETE 1101 yield 0.6 cu ft. No waste in this count.)

Round tube, not a pad

Radius is half the diameter, then converted to feet. A 12 inch tube is a 0.5 foot radius. Forty-eight inches is 4 feet. Pi × 0.5² × 4 is 3.14 cubic feet. An 8 inch tube at the same depth is 1.4 cubic feet and 3 bags. A slab or a square pier is concrete. Bag yields for a whole yard are bags in a yard.

FAQ

How many bags of concrete for a 12 inch sonotube?

A 12 inch tube filled 48 inches is 3.14 cubic feet, which is pi. At 0.60 cubic feet per 80 lb bag that is 6 bags, with no waste. A rough hole that is wider than the tube needs the extra volume typed in as a larger diameter.

Is a sonotube the same as a square footing?

No. This page is a cylinder: pi times radius squared times depth. A rectangular pad is the concrete calculator. Do not use the slab formula for a tube.

Sources

  1. QUIKRETE Concrete Mix 1101: 80 lb bag yields 0.60 cubic feet. The tube brand is not a yield. The diameter you measure is.