Pool Filter Sizing Calculator
Determine the minimum required filter size for your pool based on pool volume, desired turnover rate, and filter type. Proper filter sizing ensures effective water clarity and equipment longevity. Enter your pool details below to find the recommended filter area or tank size for DE, cartridge, and sand filters.
Enter your pool details above and click Calculate.
Formulas Used
1. Required Flow Rate (GPM):
Flow Rate = Pool Volume (gal) ÷ (Turnover Hours × 60)
2. Minimum Filter Area (sq ft):
Min Area = Flow Rate (GPM) ÷ Max Allowable Flow Rate per sq ft
3. Sand Filter Tank Diameter (inches):
Diameter = 2 × √(Min Area ÷ π) × 12
Assumptions & Standards
- DE filters: maximum 2.0 GPM per sq ft of filter area.
- Cartridge filters: maximum 0.375 GPM per sq ft of total cartridge area (conservative residential standard).
- Sand filters (high-rate): maximum 15 GPM per sq ft of sand bed area.
- Always round up to the next available filter model size — never down.