The course of the differential heats of dilution of a surfactant measured in an isothermal titration microcalorimeter is normally of sigmoidal type. The course of percolation of conductance of a water in oil microemulsion induced by either temperature or the water content of the system is also of sigmoidal nature. Derivation of the critical micellar concentration and the enthalpy of micellization (DeltaH(m)) in the former has been demonstrated to be conveniently obtained by employing the Sigmoidal-Boltzmann equation (SBE). The SBE has been shown also to be conveniently applicable for accurate determination of the threshold temperature (theta(p)) and volume fraction (theta(p)) of percolation in the latter.