How do I calculate my pond volume?

Some ponds can be notoriously tricky to accurately calculate the volume of.  Unless your pond is a perfectly regular shape such as a cuboid, a volumetric calculation is only ever a very close estimation.

The simplest way to calculate your pond volume would be to work out the surface area in m2 (square metres) and then multiply it by the depth to produce m3 (cubic metres). The volume in m3 then needs to be multiplied by 1000 to give a measurement in litres.


Rectangular pond: 3m L x 1.5m W x 0.75m D

3m x 1.5m = 4.5m2

4.5m2 x 0.75m = 3.375m3

3.375m3 x 1000 = 3375 Litres

Circular ponds are calculated differently.  You will need to firstly work out the surface area of the pond by multiplying the radius by itself and then by Pi ( πr² ). The surface area is then multiplied by the pond depth to give the volume in m3. This value should be multiplied by 1000 to give a value in litres.


Circular pond: 3m diameter x 0.6m depth

3m / 2 = 1.5m (Radius)

1.5 x 1.5 = 2.25

2.25 x π (Pi is roughly 3.14) = 7.065m²

7.065 x 0.6 = 4.239m3

4.239 x 1000 = 4239 Litres

Complex ponds such as kidney shapes will need to be closely estimated. In the case of a kidney shaped pond you would form a rectangle around all outer perimeters and estimate a percentage of what is dry land. Calculate the pond as a rectangle and the remove this percentage from the total surface area before multiplying by the depth.

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