OPUCEM: A library with error checking mechanism for computing oblique parameters

► A C/C++ library, OPUCEM, is developed to calculate the oblique parameters. ► The embedded error checking mechanism verifies the validity of the calculations. ► This free library includes corrected formulae for a number of new physics models. ► The fourth family parameter space is studied covering Dirac and Majorana cases. ► We find empirical formulae correlating masses most compatible with EW precision data.