Search for: [Abstract = "There are many methods of forecasting and estimating the costs of construction works, but they are very often complicated and require the decision\-maker to use and elaborate mathematical tools. The aim of the research was to determine the shape and course of the cost curves for selected construction projects. Based on the analysis of the collected data on investment projects in 3 facilities research groups \(collective housing, hotels and retail service facilities\), an original attempt was made to determine the best fit curve and the area of the curve, which in turn indicates the limits of the correct planning of the cumulative costs of construction projects."]