With the growth in the use of DFT for predicting elementary catalytic reaction step kinetics, it is desirable to develop approaches that provide the overall reaction (OR) rate in terms of these. Deriving an explicit rate expression for a sequence with three or more steps by solving the quasi-steady-state (QSS) equations, however, is tedious, or infeasible, and the resulting expressions are often unwieldy and difficult to interpret. As a result, the microkinetics approach is favored, providing, however, only numerical results. Here, we provide an alternate approach to obtain the QSS rate expression for a reaction sequence in analogy to an electrical circuit, i.e., OR rate = driving force/overall resistance, where the overall resistance may be obtained in terms of the individual step resistance following the electrical analogy. The individual step resistances, in turn, can be derived readily based on the traditional Langmuir-Hinshelwood-Hougen-Watson (LHHW) approach, by assuming each step in turn to be rate-limiting, combined with the notion of "intermediate reactions" for the formation of the intermediate species. This provides exact expressions for mechanisms with linear (first-order in intermediates) step kinetics in linear sequences, and approximate but accurate expressions in others. Further, it allows insightful conclusions to be drawn about one or more rate-limiting steps in a sequence, and the resulting simplifications. The approach is illustrated with the help of catalytic N2O decomposition (linear kinetics), and the hydrogenation of isobutene (nonlinear kinetics). (C) 2009 Elsevier Ltd. All rights reserved.