Natural gas can be measured in a number of different ways. As a gas, it can be measured by the volume it takes up at normal temperatures and pressures, commonly expressed in cubic feet. Other commonly used measures for natural gas are thousands of cubic feet (Mcf), millions of cubic feet (MMcf), or trillions of cubic feet (Tcf), as well as in billion cubic meters (bcm). 1 bcm of natural gas is equal to 36 trillion British Thermal Units, to 36 million mmbtu, is equal to 35.3 billion cubic feet, is equal to 17.23 thousand barrels of oil equivalent per day, is equal to 96.7 million standard cubic feet per day, is equal to 0.9 million tons of oil equivalent. While measuring by volume is useful, natural gas can also be measured as a source of energy. Like other forms of energy, natural gas is commonly measured and expressed in British thermal units (Btu). One Btu is the amount of natural gas that will produce enough energy to heat one pound of water by one degree at normal pressure. To give an idea, one cubic foot of natural gas contains about 1,027 Btus.