Knowing the square footage (also known as surface area) is essential for calculating the volume of your pond. Once you know the volume of your pond, you will be able to add and maintain the correct amount of chemicals and stock your pond correctly. Square footage is easy to calculate if you use the correct formula for the shape of your pond.
Things You'll Need
 Tape measure
 Calculator

Determine the shape of your pond. Ponds can be square, rectangular, circular or irregular in shape.

Use a tape measure to determine the length and width of a square or rectangular pond. Write down both measurements. Multiply both numbers with a calculator to get the square footage.

Use a tape measure to determine the diameter of a circular pond. The diameter is the distance from one side of the pond to the other side of the pond through the center. Divide this measurement by two to determine the radius. On a calculator, multiply the radius by Pi (3.14) to get the square footage.

Use a tape measure to determine multiple, equallyspaced width measurements across the pond from one side to the other for an irregularshaped pond. Add the width measurements together and divide by the number of individual width measurements to determine the average pond width. Take multiple, equallyspaced length measurements. Add all length measurements together and divide by the number of individual length measurements. Multiply the pond's average width and length to determine the square footage.
Tips & Warnings
 If you are measuring the square footage of a pond that is larger than a small backyard pond, use a transit instrument to take measurements, or utilize pacing.
 Measure several times to be precise. Incorrect square footage measurements lead to incorrect calculation of the volume of your pond. This will lead to excessive or insufficient chemical applications, which could be lethal to aquatic life.