Formula used
Volume = π × (diameter ÷ 2)² × average depth; U.S. gallons = cubic feet × 7.48052
Worked pond example
Pond Calculator example: π × (15.5 ft ÷ 2)² × 3 ft = 566.08 ft³. Multiplying by 7.48052 gives approximately 4,235 U.S. gallons.
Interpret gallons and flow
Use gallons for pump and treatment conversations, then confirm actual volume by fill-metering or a surveyed shape when dosing accuracy matters.
System effects the formula omits
Sloped banks, shelves, liners, irregular outlines, sediment, freeboard, and changing water level can make a circular-cylinder estimate generous.
Questions specific to this calculation
How should I handle shelves or sloped pond sides?
Enter surface diameter and a defensible average depth for a roughly circular pond; the calculation treats the sides as vertical.