Several experimental demonstrations of laser giant pulsing using a saturable absorber inside the laser cavity as a fast switch have recently been reported. In the present work giant pulse parameters such as pulse rise and fall times and peak power are calculated as a function of σ, the ratio of absorber to laser ion cross sections; nai, the normalized inversion prior to switching; and the laser mirror transmission Tr. It is shown that there is an optimum Tr for the extraction of maximum peak power. A criterion for the minimum σ for giant pulsing to occur is derived. The largest output occurs when σ → ∞ in which case the theory approaches that of Wagner and Lengyel. Some numerical examples are presented as well as a discussion of the range of validity of the theory.