1. If you have more than one wall in your job, break it down into sections.
2. Know the length and height of your wall in feet.
3. The wall is made up of rows, or courses, of concrete block.  Several courses make up the height of the wall.
4. First we will calculate how many block it takes to make one course:  Take the length of the wall and multiply by ¾ (0.75). 
5. Once you calculate how many block it takes for one course, then we will calculate how many courses or rows you need.
6. To figure the number of courses, take the height in feet and multiply by 1 ½. (1.5)
7. Now you have the number of block in a course and the number of courses for the height, just multiply the numbers together to get the total number of block.

EXAMPLE:

We have a wall 100 ft long and 8 ft high.  How many block do we need?

1. For the 100 ft length, multiply 100 x ¾ and get 75 block.  That’s how many we need in one course.
2. For the number of rows or courses, multiply the height in feet by 1 ½ (1.5).

Our wall is 8 ft. high, so 8 x 1 ½ = 12.  It takes 12 courses to go 8 ft. high

1. To get the total number of block, multiply the number of block in one course by

the number of courses. 

For our wall, that is 75 x 12 = 900 block.

Another method to calculate your wall:

This method uses the total square foot area of the wall. (Don’t confuse it with square foot area of the building).

1. Know the length and width of the wall in feet.
2. Multiply the length by the width to get the total area of the wall in square feet.
3. Multiply that number by 1 1/8 (1.125) to get the number of block needed. (It takes 1 1/8 block to cover 1 square foot)

EXAMPLE:  Let’s use our wall for the top example. It’s 100 ft long by 8 ft high.

1. Multiply 100 by 8 and we get 800 square feet of wall area.
2. Multiply 800 by 1 1/8 (1.125) – that equals 900.  

For our wall that is 900 block. (same as in the top example)

Remember that you will have to take out for any doors and windows in the wall.  A regular door is about 25 block and a window about 15 block.  A garage door is about 90 block.

Now that we have figured the number of block, we will need to know how much mortar mix and sand we will need.

For Mortar Mix, it takes about 3 bags to lay 100 block. Since we have 900 block in our wall, that 3 bags x 9 = 27 bags of mortar mix.

For the Sand, one of our “Big Bags” of sand (one yard) is enough for 9 bags of mortar mix. For this wall, we will need three big bags of sand.