A US gallon of water weighs 8.34 lbs or three.Seventy eight kg at sixty two °F (17 °C). An imperial gallon (UK) weighs 10.022 lbs or four.546 kg, at its maximum dense temperature, which is 2.20456 lbs / L at 4 °C or 39 °F.
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Ballpark Calculation (for all temperatures)
1 gallon = 3.75 liters
5 gallon = 18.75 liters
1 liters = 1 kilogram (density of water is 1 kg/liter)
1 kg is about 2.2 lbs
so, 3.75 kg is about 8.25 lbs and 1 gallon is ready 8.25 lbs
Three Different Units of Gallon
It makes a distinction which unit of gallon you are using. There are two US definitions of gallon. The US liquid gallon (most generally used) is described as 231 cubic inches, that is 3.785 liters, and weighs eight.344 lbs at its highest density.
The US dry gallon is described as 1/eighth of a US bushel, which is 268.8025 cubic inches or 4.405 L. The weight of a US dry gallon is 9.711 lbs of water at its maximum density.
The UK gallon or imperial gallon at the beginning turned into described as 10 lbs of water, but the current definition is precisely 4.54609 L or 10.02 lbs of water at its most density.