Swimming Pool Pump Size Calculator
Free swimming pool pump size calculator: US gallons or rectangular ft³ estimate, turnover hours to required GPM & L/min, scenario sensitivity rows—plus a friendly guide. Not a substitute for TDH pump curves.
Planning notice: Real pump selection depends on total dynamic head (TDH), plumbing layout, filter type, heater/chlorinator loops, and manufacturer pump curves. This tool estimates the minimum continuous flow needed to turn your pool volume over in a chosen time—useful for sanity checks and conversations with a pool pro, not a substitute for hydraulic design or local codes.
Summary: Enter your pool volume in gallons or approximate it from a rectangular length × width × average depth (feet). Pick a turnover time (hours to move one pool volume through the system). The tool outputs required GPM (U.S. gallons per minute) plus L/min for reference, then shows scenario rows—same spirit as the mortgage calculator’s stress checks—tighter or looser turnover and volume uncertainty.
What this tool does — and does not (tap to expand)
- Does: computes GPM = gallons ÷ (turnover hours × 60), converts to liters per minute, and shows how many full pool volumes per day your turnover implies (24 ÷ hours).
- Does not: read suction-side vacuum, calculate head loss, size pipe diameters, pick impeller trim, or verify NSF/health department turnover rules in your jurisdiction.
Swimming pool pump size calculator (flow rate)
Think of the headline number as the continuous flow target for sizing discussions. Your installer will still match that target to a pump curve at your system’s head—where two pumps with the same “horsepower” label can behave very differently.
Assumptions & methodology (short)
- Volume from dimensions: cubic feet = length × width × average depth; gallons = cubic feet × 7.48051948.
- Required GPM: pool gallons ÷ (turnover hours × 60 minutes).
- Liters per minute: GPM × 3.785411784.
- Rounded display: GPM to one decimal; L/min to whole liters.