The Stoechiometric Ratio (SR) is a key parameter to determine the equivalence ratio (ER) for combustion of materials, and which will play an important effect in energy conversion processes such as combustion, gasification, pyrolysis and reforming of fossil and renewable fuels. In this paper, an equation is presented that correlates the equivalence ratio (ER) with the higher heating value (HHV). From this, the SR can be calculated. The error in the analysis is calculated for 28 fuels, showing remarkable accuracy of the new. (c) 2005 Elsevier Ltd. All rights reserved.