Pool Pump Turnover Calculator
Pool turnover is how long a pump takes to push a volume of water equal to the whole pool through the filter once. Enter your gallons, then either solve for the flow rate a target turnover needs, or enter a pump's flow to see the turnover time and turns per day. The math treats gallons per minute as gallons per hour by multiplying by 60, so a 20,000 gallon pool needs about 41.67 gpm to turn over in 8 hours.
How to calculate pool turnover
- Enter your pool volume in the Pool volume (gallons) field.
- In Solve for, choose Required flow (gpm) to size a pump, or Turnover time to check one you have.
- For Required flow, enter the turnover you want in the Target turnover (hours) field.
- For Turnover time, enter the pump's flow in the Pump flow (gpm) field.
- Read the required gpm, or the turnover hours and turns per day, then Copy result.
Examples
Size a pump for a 20,000 gallon pool
Pool volume 20,000 gal, Solve for Required flow, Target turnover 8 hours
41.67 gpm required pump flow rate
Check a 40 gpm pump on a smaller pool
Pool volume 15,000 gal, Solve for Turnover time, Pump flow 40 gpm
6.25 hours per turnover, about 3.84 turns per day
Large pool with a relaxed 10 hour goal
Pool volume 30,000 gal, Solve for Required flow, Target turnover 10 hours
50 gpm required pump flow rate
Frequently asked questions
What is pool turnover?
Turnover is the time the pump needs to move a volume of water equal to the entire pool through the filter one time. It is a core measure of circulation, since water only gets filtered and treated when it actually passes through the system. Faster turnover means cleaner, better mixed water.
How does the tool calculate turnover time?
It divides the pool gallons by the pump flow in gallons per hour. Because pumps are rated in gallons per minute, the tool multiplies your gpm by 60 first. So 15,000 gallons at 40 gpm is 15,000 divided by 2,400, which is 6.25 hours per turnover.
How is the required flow rate found?
It divides the gallons by the target turnover expressed in minutes. For 20,000 gallons and an 8 hour goal that is 20,000 divided by 480 minutes, about 41.67 gpm. That is the flow a pump must actually deliver, not just its nameplate rating.
What are turns per day?
When you solve for turnover time, the tool also divides 24 hours by the turnover to show how many full cycles happen in a day of continuous running. A 6.25 hour turnover gives about 3.84 turns per day. Most pools aim for two to three turns.
What turnover should I aim for?
A common target is one turnover every 8 hours, or roughly three per day. Busy public pools and spas turn over faster, while a lightly used residential pool can run fewer hours. Match the target to bather load and how quickly the water clears.
Does a longer run time replace a bigger pump?
Partly. Running the pump longer adds turnovers per day, while a higher flow shortens each turnover. Both improve circulation, but a variable speed pump run slower for longer usually filters more water per kilowatt hour than a high flow pump run briefly.
Why might my pump not hit its rated flow?
Nameplate gpm assumes ideal conditions. A dirty filter, undersized plumbing, long pipe runs, elbows and a partly closed valve all add resistance that drops real flow. If turnover feels slow, measure actual flow with a flow meter rather than trusting the label, then enter that number here.
Do I need an accurate pool volume first?
Yes, the whole calculation scales with gallons, so a bad volume gives a bad turnover. Measure your pool and use a volume calculator for its shape rather than guessing, especially for irregular or vinyl liner pools.
Is my data private?
Yes. Everything is computed in your browser and no values are sent anywhere, so your pool details stay on your device.
Learn more
- Sizing a pool pump by turnover and flow
Use turnover to pick a pump flow rate, then check that your plumbing and filter can actually deliver it without waste.
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