Concrete blocks are construction materials used in a variety of projects. Concrete blocks are strong, durable, affordable and utilitarian, and they can be easily reinforced and built upon when added strength and rigidity is needed. The blocks come in consistent unit dimensions, which makes it easy to estimate how many you will need for any project. All you need are some basic tools and math skills to make an accurate estimation.
Things You'll Need
 Tape measure
 Calculator
 Pencil
 Paper

Measure the height and width of the area where you plan to use concrete blocks.

Calculate the area of the space by multiplying the height by the width. For example, if the height is 10 feet and the width is12 feet, the area is 120 square feet.

Estimate the number of concrete blocks needed by multiplying the area by 1.125. For example, if the area is 120 square feet, you need about 135 concrete blocks. This is an estimate for the standard block dimension, which is 8 inches by 16 inches. If you use blocks of a different dimension, you will have to adjust your estimate.

Add a 6 percent waste margin to the block estimate by multiplying the number of blocks by 1.06. If your original estimate was 135 blocks, your waste margin calls for 143 blocks.
References
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