Block walls take many forms. Do-it-yourself projects can range from simple decorative walls that enclose a patio to an entire structure such as a garage or storage building. Usually the blocks are made of brick or concrete. In all cases, you measure blocks for a block wall pretty much the same way. You want to make sure you purchase enough blocks to complete the wall but not so many that you have a large pile left over.
Measure the length of the planned wall. For example, if you are building the wall as part of a patio enclosure, you want to find the length of the patio plus any border area to be enclosed. If you are working from blueprints, look at them for the length.
Determine the height of the wall. For some projects you may need to measure. For some, such as a decorative wall, you will decide based on appearance. Again, if you are working from blueprints, refer to them for the height.
Convert the length from feet to inches by multiplying the number of feet by 12 and adding in the remaining inches. For example, if the wall is to be 30 feet and 5 inches long you would multiply 30 feet by 12 and add 5 inches, which equals 365 inches. Convert the height from feet to inches using the same procedure.
Measure the length of one block in inches. Add 1/4 inch to allow for mortar spaces. Do the same for the height of the block.
Divide the length of the wall in inches by the length of one block. For example, if the block is 16 inches long and the wall is to be 365 inches long, you have 365/16 = 22.8. Round up to the next whole block for a length of 23 blocks.
Determine how many layers of blocks high the wall will be by dividing the height of the wall by the height of one block. If the wall is to be 96 inches high and one block is 8 inches, you have 96/8 = 12.0, so you need 12 layers of blocks.
Multiply the length in blocks by the layers of blocks needed to find the number of blocks for the block wall. If the wall is to be 23 blocks long and 12 layers high, this is 23 x 12 = 276 blocks.