Woofer Box & Enclosure Calc

Subwoofer box calculator: review idealized enclosure volume and tuning from the specifications you enter. Woofer Box keeps the inputs, units, assumptions and results visible, so you can check an idealized starting point before taking a design further.

FREE CALCULATORS
• Sealed enclosure: enter Vas, Qts, Fs and target Qtc to calculate net box volume and idealized system resonance Fc.
• Circular ports: calculate effective length from net volume, tuning frequency, port diameter, count and sound speed, or solve for tuning from effective length. An optional end correction shows the corresponding physical length.
• Volume ledger: work from internal or external rectangular dimensions, or a supplied gross volume. Subtract driver, port and bracing displacement to see the net air volume.
• Switch metric and imperial units, choose display precision, and inspect the formulas and field explanations.
• Resume your last working draft. Export and restore JSON backups of local records and settings without a paid upgrade.

OPTIONAL LIFETIME PRO
A one-time in-app purchase adds local driver profiles, saved enclosure scenarios, comparison of two saved results, and CSV/text worksheets. Edit and reuse your own driver specifications, keep scenario snapshots and compare the calculated values. There is no subscription. The core calculators and JSON recovery remain free.

LOCAL WORK, CLEAR ASSUMPTIONS
Calculations and saved work operate offline. Google Play is needed to purchase or restore the upgrade; previously verified purchase proof supports offline access. Work stays in the app on your device unless you explicitly export a file through the Android document picker. A selected cloud document provider may transfer that file. No app account is required.

Sound speed and end correction are explicit assumptions. Effective port length and corrected physical length are shown separately. Enter dimensions and displacement values for your actual design; the app does not check whether a port or driver physically fits.

These are idealized enclosure equations, not measurements or predictions of real-world sound, port noise, SPL, cabin gain, power handling or construction safety. No manufacturer driver catalog, response simulation or cut-list generator is included. Verify specifications and physical design independently before building.

Built for a focused workflow: enter, calculate, inspect, and optionally save or compare.

If Speaker Box Lite is on your shortlist, this woofer box calculator can provide a numeric reference for a DIY enclosure notebook. Use the subwoofer enclosure calculator to inspect the entered geometry before drafting a construction sketch, then check material layout and real acoustic behavior separately.

Recent changes:
First release: sealed enclosure alignment, circular-port length/tuning and a net/gross volume ledger. Optional Lifetime Pro adds local driver profiles, saved scenarios, comparisons and CSV/text worksheets. JSON backup and restore remain free. Idealized starting points from your inputs.