A measure of the energy within a fuel that is equivalent to the energy contained within coal. Although coal itself is variable in composition and calorific value, a standard of one coal equivalent corresponds to 7,000 kilocalories (≈ 29.3 MJ). For examples, 1.0 kg of fuel oil is equal to 1.52 kg coal equivalent; 1.0 m3 of natural gas is equal to 1.35 coal equivalent; 1 kg of uranium-235 is equal to 27×106 kg coal equivalent.