NMR spectra are usually measured relative to a standard. For computations, this means that it is necessary to calculate the magnetic shielding tensors for a standard as well as for the molecule of interest. It is important that this is done at the same level of theory as the calculations for the molecule of interest. GaussSum keeps track of all of the standards and the levels of theory used, so that convolution of NMR spectra using relative shifts can be automated.

Settings are saved in nmrstandards.txt, whose name and location can be changed using the Settings option in the File menu.