Pool calculatorsPump calculator
Pool pump calculator
Enter your pool volume and your current pump details. We tell you the recommended flow rate and power and how much you can save each year with a variable-speed pump.
1
Your pool
Shape
Depth
Estimated volume: 0 L (0 m³)
2
Your pump & usage
Filtration hours per day12 h
Electricity price0.20 €/kWh
Season in use6 months
Water temperature24 °C
Result
Recommended flow rate
Fill in your pool dimensions to see the recommended flow rate and power.
Estimated savings with a variable-speed pump
357 €/year
Current cost476 €
With variable speed119 €
Energy saved1,786 kWh
CO₂ avoided447 kg
Indicative calculation. The flow rate uses the (volume × 5.2) / 24 rule and the savings assume about 75% less consumption with variable speed at equal filtration; real figures depend on your installation and electricity tariff.
How to choose your pool pump
To get the pump right, the flow rate must turn over all the pool water at least 3 times a day. A handy rule is: flow rate (m³/h) = (volume × 5.2) / 24, which already accounts for head losses and about 14 hours of daily operation.
If the required flow is below 15 m³/h a 1.5 HP motor is usually enough; above that, a 3 HP one is better. Recommended filtration hours depend on water temperature: a common guide is to filter for as many hours as the temperature divided by two.
Swapping a fixed-speed pump for a variable-speed one is the biggest source of savings: lowering the speed cuts consumption dramatically (by the affinity laws, half speed uses about eight times less). Filtering longer and slower costs far less and leaves the water cleaner and quieter.
Frequently asked questions
What pump flow rate does my pool need?
Work out (volume in m³ × 5.2) / 24 for the minimum flow in m³/h. For example, a 40 m³ pool needs about 9 m³/h. The pump should turn over all the water at least 3 times a day.
How many hours a day should the pump run?
A practical rule is to filter for as many hours as the water temperature divided by two: at 28 °C, about 14 hours. In summer increase the hours, and with a variable-speed pump filter longer at a lower speed.
How much do you save with a variable-speed pump?
Compared with a fixed-speed pump, energy savings are usually around 70-80% at equal filtration, because consumption drops sharply at lower speed. This calculator estimates your savings from the power, run hours and your electricity price.
Which pump power do I choose, 1.5 or 3 HP?
It depends on the required flow: below 15 m³/h, 1.5 HP is usually enough; above that, 3 HP. Oversizing the pump does not improve filtration and increases power consumption.