Enclosure Volume Calculators - Subwoofer Box Calculator

Accurate calculation of enclosure volume for your subwoofer box is essential in designing a properly functioning subwoofer. These calculators will calculate the volume for square, rectangular, triangular, trapezoidal and cylinder tube subwoofer enclosures, sealed or ported, including driver volume, bracing volume and port volume displacement. These calculators will operate with both fractions (1/4, 1/2, 3/4, etc.) and decimals (.25, .50, .75 etc.). Be sure to read the instructions for each calculator. You can ask for help and ask questions in the DIY Subwoofer forum.

For a square or rectangular subwoofer enclosure, the calculation for net volume is (width x height x depth) using internal measurements. Enter your desired box dimensions and material thickness if measuring outside dimensions. Next enter any bracing and port displacement volume if ported. If sealed leave the port volume field empty. You can calculate bracing and port volume by using the appropriate bracing and port volume calculators below. Finally, enter the number of drivers and driver volume. The manufacturer will generally furnish the driver volume. The total net volume will be output in both liters and cubic feet. You may wish to scroll down and calculate the bracing and/or port volume first and then come back to this calculator.

Example of how to measure a square or rectangular enclosure box...

This calculator will calculate the total net internal volume of a triangular or trapezoidal subwoofer enclosure. Enter your desired box dimensions and material thickness if measuring outside dimensions. For trapezoidal enclosures you will need to enter both depth measurements (Depth 1 and Depth 2). For triangular enclosures you will leave the Depth 2 field empty. Next enter any bracing and port displacement volume if ported. If sealed leave the port volume field empty. You can calculate bracing and port volume by using the appropriate bracing and port volume calculators below. Finally, enter the number of drivers and driver volume. The manufacturer will generally furnish the driver volume. The total net volume will be output in both liters and cubic feet. You may wish to scroll down and calculate the bracing and/or port volume first and then come back to this calculator.

Example of how to measure a triangular or trapezoidal enclosure...

For a cylinder tube subwoofer enclosure (sonotube or concrete tube type enclosures) the calculation for net enclosure volume is (pi x height x [diameter/2]²) using internal measurements. Enter your desired cylinder tube dimensions and material thickness if measuring outside dimensions. Next enter any bracing and port displacement volume if ported. If sealed leave the port volume field empty. You can calculate bracing and port volume by using the bracing and port volume calculator below. Finally, enter the number of drivers and driver volume. The manufacturer will generally furnish the driver volume. The total net volume will be output in both liters and cubic feet. You may wish to scroll down and calculate the bracing and/or port volume first and then come back to this calculator.

Example of how to measure a cylinder tube enclosure...

This application will help you calculate the bracing in square or rectangular enclosures with optional square or rectangular cutouts of the same size. The formula for this is (width x height x thickness) less the total volume of all cutouts. Once you have calculated the volume of your bracing, write down these figures so that you can input them in the appropriate enclosure calculator above that will be used to determine your total net volume.

Example of how to measure square or rectangular bracing with equal size square or rectangular cutouts...

This application will help you calculate square or rectangular bracing with optional round cutouts of the same size. The formula for this is (width x height x thickness) less the total volume of all cutouts. Once you have calculated the volume of your bracing, write down these figures so that you can input them in the appropriate enclosure calculator above that will be used to determine your total net volume.

Example of how to measure square or rectangular bracing with equal size round cutouts...

This application will help you calculate cylinder tube bracing with optional round cutouts of the same size. The formula for this is (pi x height x [diameter/2]²) less the total volume of all cutouts. Once you have calculated the volume of your bracing, write down these figures so that you can input them in the appropriate enclosure calculator that will be used to determine your total net volume.

Example of how to measure cylinder tube bracing with equal size round cutouts...

If you have bracing with multiple size bracing and cutouts, then this simple bracing and cutout calculator will help you determine the bracing volume to input in the appropriate enclosure calculator above. First, use the calculator to determine your overall brace volume with no cutouts. Write down the volume. Clear the entries for bracing and input the first cutout dimensions. Subtract it from your overall bracing volume that you previously calculated. Repeat these steps until you have subtracted all of your various sized cutouts from your overall bracing. If you have round cutouts, use the round cutout calculator to calculate all of your round cutouts that will need to also be subtracted from your overall brace volume. Repeat all of the above steps for multiple bracing pieces until you have calculated all of your bracing volume for your enclosure.

Example of how to measure bracing with multiple size cutouts...

This calculator will help you determine the slotted port volume used with square or rectangular enclosures. If you are using a cylinder tube port (sonotube, concrete tube or PVC pipe) scroll down and use the Cylinder Tube Port Calculator. The formula for this calculator is (width x height x depth or length of port). The key to measuring slotted ports is to be sure to measure the outside dimensions of the part of the port that is inside the enclosure, however do not include the enclosure walls if any are used for port walls. Always start from the inside wall of the enclosure. Once you have calculated the volume of your port, write down the figure so that you can input it in the appropriate enclosure calculator that you will use to determine your total net volume.

Example of how to measure square or rectangular slotted ports...

This application is used for calculating the volume of cylinder tube ports (sonotube, concrete tube or PVC pipe). The formula for this is (pi x length x [diameter/2]²). The key to measuring tube ports is to be sure to measure the outside dimensions of the part of the port that is inside the enclosure. Always start from the inside wall of the enclosure and measure to the end of the port. Once you have calculated the volume of your ports, write down the figure so that you can input it in the appropriate enclosure calculator that will be used to determine your Total Net Volume.

Example of how to measure cylinder tube ports...

Enter one of either cubic inches, cubic feet or liters and the calculator will convert the input to the other values.