The U.S. Environmental Protection Agency (EPA) developed the Superfund CASHOUT computer model to calculate the present value of the cleanup costs at Superfund sites that the government needs to collect from potentially responsible parties (PRPs). The CASHOUT computer model will assist EPA staff in developing settlement figures for Superfund de minimis settlements, commonly referred to as 'cash outs'. De minimis settlements entail the early release from liability of certain contributors at a Superfund site after they pay their fair share of the total cleanup costs. Thus, calculating the present value of cleanup costs using the CASHOUT computer model is generally the first step in 'cashing out' PRPs involved in a de minimis settlement. The 'present value' of future costs reflects the fact that a dollar today is different (i.e., worth more) than a dollar tomorrow. Cleanup costs to be incurred in the future need to be restated in terms of today's dollars to 'cash out' PRPs. Using the present value of the total cleanup costs, Agency staff can develop a basis from which they can estimate each de minimis contributor's share of the total cleanup costs.