Abstract: There is disclosed a method for determining the heating value of a fuel, the fuel comprising at least one hydrocarbon including a first hydrocarbon present in the highest molar concentration, the method comprising: measuring the stoichiometric oxidation molar flow ratio of the fuel; determining the ideal molar heating value (HVm,i) from the measured stoichiometric oxidation molar flow ratio; measuring the molar concentration of the first hydrocarbon; and determining the real molar heating value (HVm,r) from the ideal molar heating value (HVm,i) and the molar concentration of the first hydrocarbon. An apparatus is also disclosed.