The optical constants of ion-beam-sputtered SiC films have been measured by ellipsometry in the 190 to $950\mathrm{nm}$ range. The set of data has been extended both toward shorter and longer wavelengths with data in the literature, along with inter- and extrapolations, in order to obtain a self-consistent set of data by means of Kramers–Krönig analysis. All data correspond to films that were deposited by sputtering on nonheated substrates, and hence they are expected to be amorphous. A bandgap of $1.9\mathrm{eV}$ for the films was fitted from the obtained optical constants. A good global accuracy of the data was estimated through the use of various sum rules. The consistent dataset includes the visible to the extreme ultraviolet (EUV); this large spectrum of characterization will enable the design of multilayer coatings that combine a high reflectance in parts of the EUV with desired performance at a secondary range, such as the visible. To our knowledge, this paper provides the first compilation of the optical constants of amorphous SiC films.