Free geodetic networks are networks of points which absolute coordinates are not known, but only their relative position in relation to each other. This network is invariant to translation and rotation, and possibly a change in the scale. Degrees of freedom of this type of network cause singularity of the normal equations coefficient matrix N, therefore the use of general inverse is required, and the most commonly used is Moore-Penrose inverse or pseudoinverse. This paper presents available commercial software which are most commonly used in geodetic practice for network adjustment, regular, as well as singular. The mathematical solution of singular networks adjustment has been elaborated, input and output values were defined and consequently the application flowchart was made. By use of programming language C# in .NET framework in Microsoft Visual Studio, the Windows application called NetAdjustment has been developed for the adjustment of levelling and two- and three-dimensional trilateration free networks.