Concrete Calculations and Estimating

• Multiply Length by the Width to determine area.
  
• Multiply the area by the depth (Make sure the depth has been converted from inches to feet) to determine cubic feet.
  
• Most concrete is ordered by the "yard" (or cubic yard) so you must now divide the cubic feet by 27.

Example: Calculate the cubic yards of concrete for a driveway that is 12' wide, 100' long and will be poured to an average depth of 4"

• 100 X 12 = 1200
  
• 1200 X .33 = (4" ÷ 12 = .33)
  
• 396 ÷ 27 = 14.67

Pythagorean Theorem is often used for squaring. To verify a corner is square (90 Degrees)

Multiply the Height of your column by the number that corresponds to the diameter to determine the cubic yards needed.

Block Multiplier

1. Add 3/8" Mortar joint to block dimensions = 16" X 8"
   
2. 16" X 8" = 128"
   
3. 144 / 128 = 1.125 (144 is the square inches in a square foot) 1.125 Blocks per SF.

1. Add the total Linear FT of walls to be blocked.
   
2. Multiply the total Linear FT by the Height of the building to find the Area to be Blocked.
   
3. Minus the total square feet of all openings.
   

Multiply the area by 1.125.

Example: Calculate the block needed for a wall that is 50' long and 10' High. With 80 sq feet of openings.

1. 50' X 10' = 500 SF
   
2. 500 - 80 = 420
   
3. 420 X 1.125 = 473