Measure the length in feet and the width in feet with the tape measure, then measure the depth in feet with a dip stick if your pond is a square or rectangle.
2
Multiply the length by the width by the depth to get the volume in cubic feet. For example, if your pond is 16 feet long, 8 feet wide and 4 feet deep, multiply 16 by 8 by 4 to get 512 cubic feet.
3
Convert cubic feet to gallons by multiplying the cubic feet by 7.48. In this example, multiply 512 cubic feet by 7.48 to get 3,830 gallons of water in a rectangular pond.
