How to Calculate Speaker Box Volume

Rectangular or Wedge-Shaped Boxes

• 1). Measure the inside height, width and depth dimensions of the speaker box. Do not measure from the outside edges, as this will include the building material in the volume calculation. For wedge-shaped boxes, the depth will be the average of the top and bottom depths. As an example, if you measured 12 inches at the bottom and 4 inches at the top, the average depth would be 8 inches.
  
  
• 2). Multiply the height, width and depth to calculate the volume. As an example, if you measured 12 inches by 8 inches by 36 inches, the volume would be 3,456 cubic inches.
  
  
• 3). Divide the cubic inches by 1,728 to convert to cubic feet. In the example, 3,456 cubic inches divided by 1,728 yields 2 cubic feet.
  
  

• 1). Measure the inside diameter and width of the box.
  
  
• 2). Divide the diameter by 2 to calculate the radius. As an example, if you measured 12 inches in diameter, you would get a radius of 6 inches.
  
  
• 3). Square the radius. Multiply that figure by 3.14 and the width of the box. In the example, if the width was 36 inches and the radius 6 inches, you would multiple 6 times 6 times 3.14 times 36 to yield 4,069 cubic inches.
  
  
• 4). Divide by 1,728 to convert to cubic feet. In the example, 4,069 divided by 1,728 yields 2.35 cubic feet.