Crystal Ball uses Monte Carlo simulation to overcome both of the spreadsheet limitations encountered with traditional spreadsheet analysis (How Crystal Ball Differs from Traditional Analysis Tools):
You can describe a range of possible values for each uncertain cell in a spreadsheet. Everything you know about each assumption is expressed all at once. For example, you can define the business phone bill for future months as any value between $2500 and $3750, instead of using a single-point estimate of $3000. Crystal Ball then uses the defined range in a simulation.
With Monte Carlo simulation, Crystal Ball displays results in a forecast chart that shows the entire range of possible outcomes and the likelihood of achieving each of them. In addition, Crystal Ball keeps track of the results of each scenario for you.