In the oil industry, following the definition of the American Petroleum Institute, a standard barrel of oil is often taken to mean the amount of oil that at a standard pressure and temperature would occupy a volume of exactly . This standard barrel of oil will occupy a different volume at different pressures and temperatures. A standard barrel in this context is thus not simply a measure of volume, but of volume under specific conditions. The task of converting this standard barrel of oil to a standard cubic metre of oil is complicated by the fact that the standard cubic metre is defined by the American Petroleum Institute to mean the amount of oil that at 101.325 kPa and occupies 1 cubic metre. The fact that the conditions are not exactly the same means that an exact conversion is impossible unless the exact expansion coefficient of the crude is known, and this will vary from one crude oil to another.