Manually calculating enclosure volume

Caclulating Box Volume

When designing speaker enclosures, you'll need to calculate box volumes. The formulas below will help determine area and volume for shapes commonly found in box designs.

Irregular Enclosures

Measurements for box volume should always be calculated for the inside (Net) of the box. If the box is irregular, and most are, break the interior into a collection of regular shapes, calculate the volume for each shape, and add them together. For instance, a box with a slanting front and the other sides at right angles could be calculated by adding the volume of the rectangular part to the volume of the triangular part.

Conversion Formulas

After calculating the basic shapes of the box, you'll need to convert AREA into VOLUME.  The basic formulas below will help you convert AREA of traditional rectangular boxes into VOLUME.

Conversion Factors

We've included some handy conversions so you can calculate between standard and metric units.

Subtract Displacements

Don't forget to subtract the "displacement volume" of the woofer and any port tubes, internal braces, etc., from the box volume. Rockford Fosgate subwoofers have woofer displacement expressed in cubic feet (and liters) printed inside the owners manual. For ports, braces and divider displacement, use the formulas above to calculate the volume for each piece, then subtract these from the total volume of the woofer enclosure.

Helpful Hint
Always remember to calculate twice, cut once.

Woofer BoxWizard

To simplify box calculations, please use our RFTECH Woofer BoxWizard to automate your volume calculations.