Pump Flow Rate Calculator
Calculates required pump flow rate (GPM) based on pool volume and desired turnover time.
How it works
GPM = Pool Volume ÷ (Turnover Hours × 60)TDH = Elevation + Pipe Friction + Equipment ResistanceHP based on GPM vs TDH pump curve
- You enter
- Pool volume (gallons), turnover hours (desired), pipe diameter (inches), total pipe run (feet), 90-degree elbows (number)
- You get
- Required GPM, total dynamic head (feet), recommended pump HP, suggested models
How accurate is it? 8-hour turnover standard (residential); 6 hours for high-use pools; TDH depends on plumbing layout; variable-speed pumps more efficient.
These are estimates, not quotes. See How We Estimate.
Worked example
20,000-gallon pool, 8-hour turnover: 20000÷480 = 41.7 GPM needed | With 2-inch pipe, 50-ft run, 4 elbows: TDH ~45 ft → 1.5 HP pump recommended.
Tap an example above the calculator to see it worked with live numbers.
Reference table
| Pool | Common turnover goal |
|---|---|
| Residential pool | Once every 6–8 hours |
| Spa | Once every 30–60 minutes |
| Commercial / HOA | Set by local health code |
When to use it
Determines correct pump size and run time to achieve adequate filtration and chemical distribution.
Pump selection/replacement, new pool equipment planning, troubleshooting cloudy water, ensuring adequate circulation.