# How To Calculate Swimming Pool Volume in Gallons

For pool owners, finding out exactly how many gallons of water are used to fill up the pool is important not only in determining how much of a water bill you will pay, but also in maintaining the quality of water in the pool. A number of chemicals are used to maintain the cleanliness of the water, but these chemicals need to be calibrated according to the size of the swimming pool and the pool volume. If too much chlorine is added to a small pool, for instance, the swimmers can get very sore eyes and the chlorine can irritate the skin. Too little, however, and the pool will become dirty and unusable very quickly. Here's how you can compute for the swimming pool volume in gallons.

**Measure the pool**. Begin by measuring the dimensions of the pool. This means that you should have an idea of the length, the width, and the depth of the pool. Not all pools are fashioned alike however, and in some cases, the pools will have a circular or oblong shape. In this case, you will need to take the circumference or the perimeter of the pool, in relation to the depth of the pool.

**Multiply**. Once this is done, the next step is to find the volume of the pool. This can be done using the formula: L x W x H. this means that the length, the width, and the depth of the pool should be multiplied together. For example, a pool that is forty feet in length, twenty feet in width and with a depth of ten feet will have an initial volume of 8000 gallons. This, however, is only the initial gallon, because you will still need to use a multiplier. The multiplier for rectangular and square shaped pools is the constant 7.5. Therefore, the accurate swimming pool volume in gallons is 60,000 gallons.

**For round pools**. If you have a round or spherical shaped pool, then you will have to multiply the circumference by the average pool depth, and a constant multiplier of 5.9. This means that a pool which is sixty feet in circumference and which has a depth of ten feet should have a pool volume of 3300 gallons.

**Complex pools**. Keep in mind, however, that some pools are more complex than others. In these cases, you should ask the pool manufacturer for the swimming pool volume. For example, some pools are made with slanting bottoms so that small children can play on the shallow end of the pool, while adults can swim on the deeper end of the pool. In these cases, there are no simple formulas for getting the volume of the pool in gallons.

If you have complex pools, however, you can also use online pool volume calculators, which can compute for the amount of gallons that your pool can hold. These will ask for certain measurements, depending on the type of pool that you have, which you will input into the website. The site will then give you the number of gallons that your pool can hold. Some of the sites that you can visit are __PoolWizard__ and __PoolSpa__.