The importance of sorting algorithms is significant because they are used on a regular basis. For instance, while sorting files on a computer, their sequence can be determined by name, date, size etc. There are a lot of sorting algorithms which differ from each other by certain characteristics. In order to determine which of them is better or whether some of them need their performances improved, they have to be analyzed and the needed resources have to be estimated. That kind of estimation is called „a priori“ complexity analysis, whereas the real calculation belong to the „a posteriori“ one. Two basic algorithm resources are space and time. The estimation of the time required for the algorithm to resolve a specifically defined problem is shown through the T(n) function. This function isn't completely accurate because it can not define the real time of the algorithm implementation. Therefore, the real time, which is defined in time units, specifies resources more accurately. With the comparison towards the given resources, it is possible to define which algorithm is better but only for certain situations of sorting which depend on the initial sequence on content, size etc.