How the pool pump run time calculator works
One full turnover moves all your water through the filter once. Most residential pools stay clean on one turnover a day, with two in a heavy swim season or high heat.
Cost comes from motor watts times hours. A variable speed pump on low draws a fraction of the power of a single speed motor, which is why longer run times can still be cheaper.
The formula, step by step
Hours = (Gallons x Turnovers) / (Flow Rate x 60)
- Multiply gallons by the turnovers per day you want.
- Multiply flow rate in GPM by 60 to get gallons per hour.
- Divide the first number by the second for daily hours.
- Cost = motor kilowatts x hours x your power rate.
Worked example
A 20,000 gallon pool with a pump moving 50 GPM, one turnover a day.
50 x 60 = 3,000 gallons per hour. 20,000 / 3,000 = 6.7 hours.
At 1.1 kW and 16 cents a kilowatt hour, that is about 1.18 dollars a day, or 35 dollars a month.
Watch it done
This short video walks through the same job in real life, so you can match what you see on screen to what you do at the pool.
Tips before you start
Split the run time. Four hours in the morning and three in the late afternoon keeps the surface clean during the hours people actually swim.
Run the pump during the hottest part of the day in algae season. Chlorine burns off fastest then, and circulation keeps it moving into corners.
Pool Pump Run Time Calculator FAQs
How many hours a day should a pool pump run?
Enough for one full turnover, which is usually 6 to 8 hours for a residential pool. Push it to 10 or 12 during a heat wave.
Can I run the pump at night only?
You can, and off peak power is cheaper. Just add a short midday run when the pool is busy or the water is warm.
Does a variable speed pump need longer run times?
Yes, because low speed moves less water per minute. It still costs less overall, since power use drops much faster than flow does.