Gallon is the most commonly used measuring unit. It is very much essential to quantify the mass and volume of materials for the purpose of inquiring scientific measurements. In order to use any material for the purpose of industrial production it is very much important to measyre the physical quantities including mass, volume and many more physical quantities. In USA when it comes to measuring liquids we often use volume as specified in liters or gallons. Gallon is the most commonly used unit in order to specify the volume of liquid  in USA and UK. The volumes of most of the liquids starting from gasoline to cans of water all of them are quoted in liters. In US this measurement is dealt with gallon. While summarizing the weight of one gallon of water weighs to about 3785.41178 gm. For the purpose of uniformity usage all the units of measurement is standardized according to their national and international units. Among all the three definitions of gallon, the one that is commonly used is the US liquid gallon. Measurement of one US gallon of liquid is defined to as 231 cubic inches which is equivalent to 3.785411784 liters. Since the measurement of 1 liter of water is equal to 1000 cubic centimeters the measurement of US liquid gallon is equal to 3.785.411784 cc. This approximately equals to 0.133680555 cubic feet. From the knowledge of the volume and density of a liquid the mass of water can be calculated. Hence the relation can be stated as

Density= Mass/ Volume

Weight of 1 gallon of water in grams:

A gallon of any liquid is equal to 3785.411784 cc. The density of water at a normal temperature ranges to approximately 1 gm/cc. Hence the weight of one gallon of water in gram is equal to 3785.41178 gm. Hence in kilogram it will weigh about 3.78541178 kilograms.

Weight of one gallon of water in pounds:

By equation, the measurement of one kilogram is equal to 2.20462262 pounds and the measurement of one gallon of water is equal to 3.78541178 kg. Therefore the weight of one gallon of water is equal to (3.78541178 × 2.20462262) lbs which is equal to 8.3454 lb.

Weight of one gallon of water in ounces:

The weight of one gallon of water in ounces is equal to 133.526471 Oz.

Weight of a gallon of salt water:

The weight of a gallon of salt water varies according to the dissolving amount of the salt. The total mass of salt water is equal to the mass of water in addition to the mass of the dissolved salt. So the density of the dissolved salt and the density of salt needs to be known prior calculating its weight. In order to determine the perfect weight of salt water a standardized digital balance is thus used to get an accurate value for the measurement. While calculating the conversion between the different weights of water forming a chart between the different conversion levels of water helps in providing information for a regular basis.