Calculating How Much Dirt is Needed for a Square Area
- Determine square footage of area. This is length x width.
- Determine depth of needed soil in inches.
- Take the square footage and multiply be depth in decimal. For instance 6” is .5 in decimal. To figure out decimal take inches and divide by 12. For instance 7 inches divided by 12 is .58. This number is the cubic feet needed.
- Then divide this number by 27. This will tell you how many cubic yards of pulverized soil is needed.
Example:
A raised garden bed of 8 x 8 is 64 s.f. It is 18” high. (18 divided by 12 = 1.5)
This is 1.5 in decimal.
Multiply 64 x 1.5 = 96. This is the cubic feet needed.
Divide by 27 . (96 divided by 27 = 3.56)
3.56 cubic yards of dirt is needed
Calculating How much Dirt is Needed for a Circle
- Determine square footage of area. Area of a circle is the radius squared x pie which is 3.14. (18’ pool is a 9’ radius. 9 x 9 = 81 x 3.14=254.34 s.f.)
- Determine the depth in inches then convert to decimal. Depth in inches divided by 12. For instance 4” – 12 = .33
- Multiply square footage by depth to determine cubic feet. (254.34 x .33 = 83.93 cubic feet)
- Determine cubic yards needed. Cubic feet divided by 27 = cubic yards. For our example 83.93 divided by 27 = 3.11 cubic yards.