The calibration of a pressure balance implies to determine the values of the zero-pressure effective area 0 and the pressure distortion coefficient that defines the piston-cylinder assembly effective area .In order to analyze this behavior, this work compares the method of ordinary least squares with the generalized least squares and weighted least squares to calculate the contributions to type A uncertainty, in particular the residual deviation.For this purpose, an interactive application has been built in R-Shiny, which allows for getting the results mentioned.