This paper presents the Pareto Calculator, a tool for compositional computation of Pareto points, based on the algebra of Pareto points. The tool is a useful instrument for multidimensional optimisation problems, design-space exploration and development of quality management and control strategies. Implementations and their complexity of the operations of the algebra are discussed. In particular, we discuss a generalisation of the well-known divide-and-conquer algorithm to compute the Pareto points (optimal solutions) from a set of possible configurations, also known as the maximal vector or skyline problem. The generalisation lies in the fact that we allow for partially ordered domains instead of only totally ordered ones. The calculator is available through the following url: http://www.es.ele.tue.nl/pareto.