Approximately how much does water weigh per gallon?

Approximately how much does water weigh per gallon?

• A. 7.5 lb per gallon (3.4 kg)
• B. 10.5 lb per gallon (4.8 kg)
• C. 8.3 lb per gallon (4 kg)
• D. 12.2 lb per gallon (5.5 kg)

Answer: (C)

Water weighs about 1 kilogram per liter. A US gallon is 3.785 liters, so a gallon of water is roughly 3.785 kilograms, which is about 8.34 pounds. Therefore, 8.3 pounds per gallon is the closest approximation. The other values are off for a US gallon: 7.5 pounds is too light, while 10.5 and 12.2 pounds are heavier than a full US gallon of water. (If you were using an imperial gallon, a gallon would be about 10.02 pounds, which would make the 10.5-pound option plausible in that context.)

Water weighs about 1 kilogram per liter. A US gallon is 3.785 liters, so a gallon of water is roughly 3.785 kilograms, which is about 8.34 pounds. Therefore, 8.3 pounds per gallon is the closest approximation. The other values are off for a US gallon: 7.5 pounds is too light, while 10.5 and 12.2 pounds are heavier than a full US gallon of water. (If you were using an imperial gallon, a gallon would be about 10.02 pounds, which would make the 10.5-pound option plausible in that context.)