Garden pond volume calculator
A natural pond shape is somewhere between a box and a bowl. A shape factor is the practical way to allow for it.
Pond volume
10 200L
- In US gallons
- 2695
- Liner length needed
- 7.20
- Liner width needed
- 5.20
- Liner area
- 37.44
- Fish length per 100 litres
- 1.47 cm
- Suggested maximum fish length
- 255
- Suggested pump flow Circulating half the volume every hour is a common target.
- 5100 L/h
- Surface area
- 12.75
Show the working
- Maximum length = 5
- Maximum width = 3
- Average depth = 0.8
- Shape = 0.85
- Total fish length = 150
- Liner overlap each side = 0.3
- volume_m3 = 5 * 3 * 0.8 * 0.85 = 10.2
- Pond volume = 10.2 * 1000 = 10 200
- In US gallons = 10 200 / 3.785411784 = 2694.55
- Liner length needed = 5 + 2*0.8 + 2*0.3 = 7.2
- Liner width needed = 3 + 2*0.8 + 2*0.3 = 5.2
- Liner area = 7.2 * 5.2 = 37.44
- Fish length per 100 litres = 10 200 > 0 ? 150 / (10 200/100) : 0 = 1.470 59
- Suggested maximum fish length = 10 200 / 100 * 2.5 = 255
- Suggested pump flow = 10 200 / 2 = 5100
- Surface area = 5 * 3 * 0.85 = 12.75
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- volume = length x width x depth x shape factor
- liner size = pond dimension + twice the depth + overlap
Koi need far more space than the general rule suggests: 1000 litres per adult fish is a common minimum.