This paper provides a pragmatic approach for calculation of equilibrium constants that have been determined from systems at equilibrium by measuring a component of the equilibrium at several (minimum of three) different temperatures. The paper builds on previous work that has shown by selecting appropriate temperatures so that the van't Hoff isochore could be written in terms of the total amount of a measured analyte (A(total)) associated with the equilibrium, equilibrium constants could be determined. This paper describes a mathematical method that uses the linearity of the van't Hoff plot, In K versus 1/T as the basis to systematically test for an appropriate A total value and derive the best values of equilibrium constants. It will also show that this method is freed from constraints in choosing the study temperatures. (c) 2004 Elsevier B.V. All rights reserved.