Flow Calculators

This page contains two calculators to help you select the right size pump. The calculators will calculate the flow required, you can then choose a pump which can deliver this flow at the head required. The head is the maximum height, measured from the surface of the pond, to which the water will be pumped. It is not measured from the top of the pump.

These calculators assume that the waterfall / filter is close to the pond. Very long pipe runs will require a more powerful pump.

The first calculator is for use when you want a waterfall of a particular size. The second calculator is for calculating the flow required to filter your pond if you have fish. After the water has passed through the filter it can be returned to the pond via a waterfall, if desired. The calculator shows the approximate width of the waterfall that would be supplied. Remember that if the waterfall is higher than the filter it will increase the head requirement.

Waterfall Width Flow Calculator

Select waterfall width required  
Tick box (by clicking) if you also wish to run a fountain from the same pump  
Flow required in litres per hour =

Filtration Flow Calculator

If you do not know the volume of your pond, or need to convert from gallons please see our volume calculator page.

Enter volume of pond in litres  
Tick box (by clicking) if you also wish to run a fountain from the same pump  
Tick box (by clicking) if your fish are koi carp  
Flow required in litres per hour =
If the flow from the filter is returned to the pond via a waterfall - approx width in cm =  
Waterfall - approx width in inches =  

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