A simple approach is introduced for calculating heats of detonation via composition of explosive and its gas phase heat of formation that can be calculated by group additivity rule. There is no need to use any experimental and computed data of explosive. Two correlations are introduced for desk calculation of heat of detonation of aromatic and non-aromatic explosive compound that contains the elements of carbon, hydrogen, nitrogen and oxygen. Predicted heats of detonation for 37 explosives have a root mean square (r.m.s.) of deviation for experiment of 0.64 kJ/g, which show good agreement with respect to measured values for oxygen-lean and oxygen-rich explosives. (c) 2004 Elsevier B.V. All rights reserved.