About
Sub Box Calculator is made for people who build their own subwoofer boxes: box design, plans, cut sheets and CNC files in one place, for free.
How accurate is it?
It is built on the Thiele/Small model with box losses, port end corrections and car cabin gain. Results are checked against WinISD and Hornresp on reference designs, and those checks run as automated tests for every release.
Your data
No signup needed: your project is stored in your browser. Save it to a file or share it as a link — the project settings are stored in the link itself.
Contact us
Found a bug, or your sub isn’t in the database? Send us a note with the Feedback button in the calculator.