US liquid gallons
A US liquid gallon is a volume measurement used in the United States for liquids such as water, gasoline, and milk. One US liquid gallon is about 3.78541 liters. A standard bathtub is about 80 gallons of water and a car gas tank can hold anywhere between 12 and 20 gallons of gas.
US oil barrels
A US oil barrel, also known as a petroleum barrel, is a volume unit used in the oil and gas industry to measure crude oil or liquid petroleum gas (LPG). One US oil barrel is 42 US gallons or about 159 liters.