“…Successful completion of a construction project means that its completion has been completed within the assumed budget, at the scheduled time, in accordance with the expected quality, and taking into account all investor requirements. In the literature, many studies can be found regarding the analysis of construction projects due to their costs (Juszczyk, Leśniak & Zima, 2018;Wieczorek, Plebankiewicz & Zima, 2019), time (Ibadov & Kulejewski, 2015;Krzemiński, 2017), organizational aspects (Hoła, 2015;Kozlovska, Mackova & Spisakova, 2016;Lendo-Siwicka, Połoński & Pawluk, 2016;Nowotarski, Pasławski & Matyja, 2016;Grzyl, Miszewska-Urbańska & Apollo, 2017;Nowogońska & Cibis, 2017;Hanak & Korytarova, 2018), safety issues (Hoła & Szóstak, 2015), or the use of innovative solutions in construction fi led (Mrówczyńska, 2011;Kapliński, 2018). Yet, it is the calculation of costs that is one of the most important aspects of construction projects, both from the investor's and contractor's point of view.…”