Pool Calculator

The calculator relies on geometric formulas tailored to standard pool shapes, accounting for varying depths. For a rectangular pool, the volume is derived by multiplying the length by the width, then multiplying by the average depth (calculated by adding the shallow end depth1 and deep end depth2, then dividing by two). For an oval pool, the footprint is calculated using the ellipse area formula (pi multiplied by length and width, divided by four) before multiplying by the average depth. To estimate the fill cost, the total cubic volume is converted into thousands of units and multiplied by your local water utility rate.

Imagine you are planning to fill a rectangular backyard pool that is 30 feet long, 15 feet wide, with a shallow end depth (depth1) of 3 feet and a deep end depth (depth2) of 7 feet. First, find the average depth by adding 3 and 7, which equals 10, and dividing by 2 to get 5 feet. Next, calculate the volume: multiply the length (30) by the width (15) to get 450 square feet, and multiply that by the average depth (5) to yield 2,250 cubic feet. Because one cubic foot contains roughly 7.48 gallons, your pool holds approximately 16,830 gallons of water. If your local water utility charges $0.005 per gallon, filling the pool will cost about $84.15.

Always measure your pool dimensions multiple times to ensure accuracy, as even a small error in width or depth can drastically change your total gallon estimate and lead to incorrect chemical dosing. When calculating average depth for sloped bottoms, make sure you measure from the waterline rather than the top of the coping. Keep in mind that evaporation and splash-out will require periodic top-offs, so it is wise to budget a small buffer for ongoing water replenishment.