Pool Pump Size Calculator

To calculate pool pump size: 1) Calculate your pool's volume in gallons (Length × Width × Avg Depth × 7.5 for rectangular pools), 2) Divide by desired turnover time (8 hours is standard) to get GPH, 3) Divide GPH by 60 to get required GPM, 4) Match GPM to pump horsepower using manufacturer charts. For example, a 24,000-gallon pool needs 50 GPM (24,000 ÷ 8 ÷ 60), which typically requires a 1 HP pump.

For a 35,000-gallon pool with an 8-hour turnover, you need approximately 73 GPM (35,000 ÷ 8 ÷ 60 = 72.9). This typically requires a 1.5 to 2 HP pump for an inground pool (50-60 TDH) or a 1.5 HP pump for an above-ground pool (30 TDH). If you have additional features like a spa, waterfall, or pool cleaner, consider going with a 2 HP pump.

Choose based on your pool size and features: A 1 HP pump is suitable for pools up to 25,000 gallons with standard plumbing. A 1.5 HP pump is better for pools 25,000-35,000 gallons or if you have additional water features, a spa, or longer pipe runs. If your pool is between sizes, the 1.5 HP offers more flexibility. Variable-speed pumps can adjust to your needs and save up to 80% on energy costs.

A 24-foot round above-ground pool holds approximately 13,500 gallons (assuming 4 ft average depth). For an 8-hour turnover, you need about 28 GPM. A 1 HP pump is typically sufficient for this size. For above-ground pools up to 24 feet, 1 HP is standard; pools larger than 24 feet usually need 1.5 HP.

Turnover rate is the time needed to circulate all pool water through the filter once. The standard is 8 hours for residential pools, meaning all water passes through the filter 3 times in 24 hours. Faster turnover (6 hours) improves filtration but uses more energy. Slower turnover (10+ hours) may not adequately filter the water, leading to algae and water quality issues.

Total Dynamic Head (TDH) measures the total resistance to water flow in your pool system, expressed in feet. It includes vertical lift, pipe friction, filter resistance, and other equipment. Inground pools typically have 50-60 TDH, while above-ground pools average 30 TDH. Higher TDH requires more powerful pumps to maintain adequate flow.

Yes, but it's not recommended. An oversized pump can damage your filter, increase energy costs, and cause cavitation (air bubbles that damage the pump). It may also exceed the flow rate limits of your plumbing (42 GPM for 1.5" pipes, 73 GPM for 2" pipes). Always match your pump to your pool size and plumbing system for optimal efficiency.