The ability to measure a yard of gravel is important for estimating material needs and costs. The term "yard of gravel," actually refers to cubic yards, a measure of volume. To determine the amount of gravel needed for a landscaping project or a construction job, measure the site where it is to be used and then convert the measurements into cubic yards. When gravel is purchased, the vendor often measures the amount by the number of loader buckets he supplies. He knows exactly how many cubic yards of gravel the bucket will hold.
Things You'll Need
 Measuring tape
 Calculator

Measure length and width of the area to be graveled and determine the desired thickness of the gravel layer. If the area is a circle, measure the diameter instead of length and width. Record all measurements in feet.

Calculate the number of cubic feet of gravel by multiplying the length times width, times depth or thickness. If the area is a circle, divide the diameter by two to obtain the radius length, and then square the radius, multiplying the number by itself. For example, if the radius is 7 feet, the squared number is seven times seven, equaling 49 feet. Once the radius is squared, multiply the number by 3.14 which is phi. The answer to this multiplication is the circle's area. Now multiply the area by the desired depth to obtain the needed cubic feet.

Divide the number of cubic feet by 27 to derive the number of cubic yards. There are 27 cubic feet in one cubic yard.
References
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