Buying concrete blocks is expensive. You've finally saved enough money to begin building the wall around your garden that you've always wanted. The neighbor's dog has dug under your fence for the last time. But how do you know how many concrete blocks to buy at the supply store? How do you spend only what you need to, and not waste any money? I'll show you how. The formula is quite simple, and accurate.
Figure out how long the wall is going to be in feet. None of it makes sense, if you don't know how long the walls will be.
Figure out how tall the wall is going to be in feet. In addition to knowing the length, without the height, the rest of the project is sunk.
Multiple the height in feet by 1.5. That will give you the number for courses needed for the wall. In other words \: How many blocks tall? This is important and will be an important part of the overall formula.
Now, for the length of the wall, you need to multiply the number of feet by .75. That will give you the number of blocks needed to lay down a single course.
And finally, multiply the two numbers together, and you have the total number of concrete blocks needed to build your wall.
As an example, a 8 foot high, 20 foot long wall will work out like this: 8 feet high times 1.5 = 12, 20 feet long times .75 equals 15. 12 time 15 is 180 full blocks, and you have a complete wall ready to keep the neighbor away forever. Good luck!