Article: You need to calculate the volume of the particular body of water you are interested in. To do this, you need a rough estimation of the total area of the surface of the body which you will then multiply by the depth.  If you are looking at a rectangular swimming pool, you will simply use length times width to find the area. If the body of water is more of a circular lake or pond, you will want to use an equation for the area of a circle. If you want to estimate the weight of an ocean, it is best to look up the total area of the ocean itself. To calculate the surface area and volume, you will need to either look up some measurements or take them yourself. Use measuring tools such as long tape measures (often used for surveying) for your estimations.  If the body of water is mostly rectangular, you want to measure the approximate length and width of the body. If the body is circular, you will need to estimate its radius. To find the diameter, simply multiply the radius by 2. Once you have assessed the shape of the body of water and made measurements, you can calculate the approximate area that the surface of the body takes up. The area calculation will be based on the shape that you previously determined when assessing the body of water at the beginning.  For a rectangle shape, simply multiply the length times the width. Let's say you had a small pond in your yard that was 100 feet by 50 feet. The total area of the pond would be 5000 ft2. For a circular shape, use the formula A = πr2 where r is the radius of the body of water. Let's say your pond was more of a circular shape with a radius of about 200 feet. The area of the pond would be π(200)2 = 125,600 ft2. To estimate the average depth, take measurements evenly spaced throughout the entire pond from both the shallow and deep areas. Add up all of these measurements and then divide by the total number of measurements. This will give you a good estimation of the average depth of the body. Alternatively, you can try to look up the depth of the body of water if it is well-known lake or ocean. The final step in calculating the volume of the body of water is to multiply the total surface area by the average depth. Remember, this is still an approximation because some liberties were taken with the measurements. For example: Let's say the rectangular pond had a depth of 150 feet. It had a surface area of 5000 ft2 so multiplying that by 150 feet gives you an approximate volume of 750,000 feet3.

What is a summary?
Assess the shape of the body of water. Take measurements of the body of water. Approximate the surface area of the body of water. Estimate the average depth of the body of water. Multiply the total surface area and depth to calculate the volume.