calculate gallons in a pool
Since there are 7.5 gallons in each cubic foot, multiply the cubic feet of the pool by 7.5 to arrive at the volume of the pool (expressed in gallons). Measure the length, width, and average depth of the pool, rounding each measurement off to the nearest foot or percentage of one foot.One inch equals 0.0833 feet.ultiplying that by the depth gives the volume in cubic feet. Since there are 7.5 gallons in each cubic foot, multiply the cubic feet of the pool by 7.5 to arrive at the volume of the pool, expressed in gallons.