Pea gravel is made up of small, peasized stones. People use pea gravel to line walkways and cover gardens. Stores sell pea gravel by weight. Most likely, you'll know the volume of pea gravel you need, but not the weight. Apply a little math, and you can quickly find out how much pea gravel will suit your needs.
Things You'll Need
 A calculator
 Tape measure
Calculating Gravel Volume and Weight

Measure the dimensions of the area where you want your pea gravel. This includes measuring the length of the longest side, the length of the shortest side, and the depth.

Convert all measurements into feet by dividing by 12. For example, if you have a depth of 7 inches, dividing by 12 would give you 0.583333 feet (or about 0.6 feet rounded).

Multiply your three dimensions together (longest side, shortest side, and depth) to find the volume in cubic feet.

Multiply your cubic feet by 96 to find the total number of pounds you'll need. (A single cubic foot of pea gravel weighs about 96 pounds.)

If you are covering a very large area with pea gravel, you'll need to convert to cubic yards. Simply divide your cubic feet by 27.

Multiply your cubic yards by 1.3 to find the total number of tons you'll need. (A single cubic yard of pea gravel weighs about 1.3 short tons.)
Tips & Warnings
 Typically, you can round numbers to one decimal point. Look at the number just to the right of where you want to round. If it is 5 or higher, round your digit up. If it is 4 or lower, leave the digit alone.
 Gravel can settle. This means that you may have to buy 5 to 10 percent more gravel than you anticipated.