Designing a pond

How to get the design and planning stage right first time.

Building ponds

Where, how and what materials and equipment. The hard work bit.

Koi Pond Pumps

How to choose and where to buy your koi pond pump.

Koi Pond Filters

Selecting the correct filter for your koi pond.

Koi Pond Food

Choosing the right food to keep your koi fit and healthy.


Pond Measurements and Conversions.

How to calculate the pond liner size

To calculate the amount of liner you need for your koi pond, you need to know the measurements of the pond. Sketch out a plan of how you want the pond to look and calculate the width and length of your pond. Use average width and length if the pond is not square or oblong. The final measurement you will need is the maximum depth of your pond.

Liner length = max length + (2 x max depth) + 1 (for overlap)
Liner width = max width + (2 x max depth) + 1 (for overlap)

So for a pond of 5 by 4 metres, 1 metre deep: -

Pond liner length = 5+2+1 = 8 metres
Pond liner width = 4+2+1 = 7 metres

You'd need a pond liner that is 8 metres x 7 metres.

Incidentally, this pond would hold 20,000 litres (not including filter system)

Now you can go to the pond liner page and select the type of liner you would like.

Calculating Pond Capacity

It is important to calculate the correct pond capacity to enable the right level of filtration to be chosen for your pond and a to give a guide on a minimum flow rate to work in conjunction with any filter.

To do this, again measure the length, the width and the depth of your pond in feet. If your pond is not a regular shape you will need to work out the average of all sizes and use this to calculate the capacity.

Once you have all three dimensions you need to multiply these all together, and then multiply this calculation by 6.25.

e.g. a pond that is 10 ft long and 5ft wide and 4ft deep would use the calculation:

10 x 5 x 4 = 200

200 x 6.25 = 1250 gallons

Remember this is only an approximate guide.

If you require this capacity in litres which most companies now work with you will need to multiply the number of gallons by 4.5

e.g. calculate the number of litres by knowing the pond is 1250 gallons:

1250 x 4.5 = 5,625 litres

Again this will give you an approximate guide.

You can reverse this calculation to find the number of gallons from a known number of litres.

e.g. calculate the number of gallons by knowing the pond is 1250 litres:

1250 / 4.5 = 1250 gallons.


Weight of Water

Just remember: -

  • A pint of water weighs a pound and a quarter
  • A gallon weighs ten pounds.


This table will help you with converting units from one type to another (for example 1 Imperial Gallon/min = 0.16 Cu. Feet/min, 4.55 Litres/min or 0.005 Cu. Metres/min) ...

Unit Imp Galls/min Cu Feet/min Litres/min Cu. M/min
Imp. Gallons 1 0.16 4.55 0.005
Cu. Feet 6.23 1 28.32 0.028
Litres 0.22 0.04 1 0.001
Cu. Metres 220 35.32 1,000 1


Gallons to Litres and much more.....

To convert gallons to litres multiply by 4.546

To convert gallons to US gallons multiply by 1.2

To convert US gallons to litres multiply by 3.78

To convert cu.feet to gallons multiply by 6.23

To convert cu.feet to US gallons multiply by 7.48

To convert inches to cm multiply by 2.54

To convert feet to metres multiply by 0.305

To convert pounds to kilograms multiply by 2.2

To convert sq. feet to sq. metres multiply by 0.093

Of course to convert in the other direction you divide by the factor.

For example to convert litres to gallons you would divide by 4.54

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