How many yards od drainage stone is needed for a trench 40ft long 3 ft wide and 3 feet deep?

To calculate the volume of drainage stone needed for a trench, first find the volume in cubic feet: 40 ft (length) × 3 ft (width) × 3 ft (depth) = 360 cubic feet. Since there are 27 cubic feet in a cubic yard, divide the total volume by 27: 360 ÷ 27 = approximately 13.33 cubic yards. Therefore, you will need about 13.33 yards of drainage stone for the trench.