Planning heuristic
Pool filter cartridge size calculator
Estimate a starting filter area from pool volume. This does not identify a replacement cartridge or override equipment specifications.
Enter pool volume or dimensions
If gallons are known, use that value. Otherwise, rectangular dimensions estimate volume at 7.48 gallons per cubic foot.
Methodology
The calculator estimates flow as pool gallons divided by an eight-hour turnover, then applies a common cartridge-filter rule of thumb of about 1 square foot per 375 gallons. The result is rounded up to the next 5 square feet.
Heuristic only: plumbing, pump curves, local codes, bather load, debris, and the filter housing’s certified flow rate are not modeled. Manufacturer specifications override this estimate.
Read the filter square-foot guide, then browse cartridges by measured size.