Calculate approximate volume
Estimated water volume4,080 litres≈ 897 UK gallons
Estimate only. Rocks, shelves, baskets and equipment displace water.
The calculation
Length × width × average depth × 1,000 × shape factor = litres
Use maximum length and width, but average water depth—not the deepest point. Shape factors are useful planning corrections rather than exact geometry.
From volume to turnover
A lightly stocked wildlife pond can circulate more slowly than a koi pond. Volume is only the first input: fish load, waterfall demand, pipework and vertical lift all affect the final choice.
Do not size from volume alone
A pump’s installed flow falls as it pushes water uphill and through pipework. Continue with the real-world flow guide.