If you're involved in heavy industry or manufacturing then conveyor belts are part of your life. Whether it's short conveyor belts for transporting electronic components along a production line, or long, heavy duty conveyor belts for moving coal or other material, eventually you will have to replace the belt. Replacement can be an expensive proposition so it's important you know exactly how long and wide you need the belt to be. This information will also be helpful for transport purposes.

Determine the core diameter of your rollers. Most commercial rollers are 8 inches in diameter, but you can either measure directly or consult your roller manufacturer to find out for sure.

Determine the gauge, or thickness, of your conveyor belt. Belt gauges generally run from between 0.1 inches to 1.3 inches, depending of the application. You can either measure directly or ask your belt manufacturer for the belt specifications. For example, you might have a belt that is 0.5 inches thick.

Determine the overall diameter of the roller plus the thickness of the belt. For example, if the conveyor belt you are using is 1/2inch thick, the overall diameter is the core diameter, 8 inches, plus twice the thickness of the belt, 1 inch, for a total of 9 inches.

Multiply the overall diameter by itself. In the example 9 times 9 is 81.

Multiply the core diameter by itself. In the example, 8 times 8 is 64.

Multiply your previous two answers together. 81 x 64 = 5,184.

Multiply the belt thickness by a conversion factor of 15.28. In our example the thickness is 0.5 inches. Thus the equation would be: 15.28 x 0.5 = 7.64.

Divide your answer in step 6 by your answer in step 7. In our example, 5,184 divided by 7.64 is approximately 678.53. Your belt should be 678.53 feet long.
Tips & Warnings
 If you want to calculate the diameter of a coiled roll instead of the total linear length, take the square root of the thickness times the length times 15.28 plus the core diameter squared.