Pool Pump Size Calculator

What Flow Rate Does Your Pool Need?

Gallons per minute = gallons ÷ (turnover hours × 60)

Worked public-pool example, not a home default: 15,000 gallons over the 6 hour MAHC maximum for other public pools is 41.7 GPM. Source: CDC, 2023 Model Aquatic Health Code (MAHC), §Table 4.7.1.10. No CDC endorsement implied; available free at cdc.gov.

Worked public hot tub example: 400 gallons over 0.5 hours is 13.3 GPM. The 0.5 hour row is the MAHC turnover for a public hot tub at 93 to 104 F. Source: CDC, 2023 Model Aquatic Health Code (MAHC), §Table 4.7.1.10. No CDC endorsement implied; available free at cdc.gov.

A residential turnover time, including the figure sometimes quoted as 8 hours, is not verified. Leave it out. Enter hours from your equipment manual or from the local code that applies to you.

Pool Pump Size Calculator Results by Turnover

Same 15,000 gallon sample, three different hour entries, so you can see the division. Only the 6 hour row is a cited public-code maximum.

Common Mistakes With the Pool Pump Size Calculator

• Treating 6 hours as the right turnover for a backyard pool. That row is a public-code maximum for a class of public pools.
• Dropping in an 8 hour home default. That number is not verified here.
• Forgetting the 60. Hours have to become minutes before the flow is in gallons per minute.