This computer model complements the report by FDF: Pricing principles for digital geographic data for the Office of Geographic Data Co-ordination. The model is fully described in this report and an abridged version is incorporated in this software. The model illustrates the relationship between demand and cost, and allows the user to compute Ramsey pricing values and revenues for multiple products. An individual pricing model is also provided called SIMPLE.XLS, however its useage is not covered in this manual. In the Ramsey pricing model, the user specifies demand and cost conditions, and the model computes price, quantity, revenue and other variables to produce an optimal pricing strategy. The model can also operate within a stochastic framework, performing Latin Hypercube simulation of variables. The model’s operation is illustrated for the OGDC’s road network data sets. Applications required This model operates with Windows 3.1 or Windows 95 and Excel 5 or successors. The stochastic modelling is supported by @Risk. Scope The manual demonstrates Ramsey pricing. But the manual is based on a computerised spreadsheet model, RAMSEY.XLS, which has a potentially wider application. We provide a generic version of RAMSEY.XLS, called STOCHAST.XLS, which can be used to demonstrate other pricing regimes alomg with the stochastic analysis. STOCHAST.XLS is a ‘stripped down’ version of RAMSEY.XLS: it lacks the data entry screens of RAMSEY.XLS, but thereby offers flexibility in which data are entered, and in how mathematical relationships are formulated. However, users may need a knowledge of Solver and Excel to use STOCHAST.XLS to emulate these other pricing regimes.