step. Then the leading terms in the computational effort maybe written as 𝑎𝑛 <:2% 𝑛 = + 𝑏𝑛 ; , where 𝑛 <:2% is the number of CCSD iterations, and a is a constant. These scalings apply to increasing the size of homonuclear systems, where the number of contracted basis functions is proportional to the number of atoms. When one considers the effect of increasing the basis set size for a given molecule, it is useful to recognize that 𝑛 is the sum of the number of occupied orbitals 𝑛 $ and the number 𝑛 > of virtual orbitals, because changing the number of contracted functions changes 𝑛 > but not 𝑛 $ . Using 𝑛 > and 𝑛 $ rather than n, the leading terms in the cost are 𝑐𝑛 <:2% 𝑛 $ , 𝑛 > ? + 𝑑𝑛 $ @ 𝑛 > ? , where c and d are constants. The dependence on the number of contracted functions for a given molecule is thus less steep (asymptotically 𝑛 ~ 𝑛 > , so the scaling becomes 𝑛 ? rather than 𝑛 ; ); nevertheless, it is still very significant. As the size of the molecule increases, the difference in the number of basis functions between the jun and aug basis sets, as well as between the jul and aug basis sets, becomes more pronounced. For DZ, Table shows that the number of contracted basis functions in the aug basis set is 18-46% more than in jun and 8-24% more than in jul, where in the comparison to jul we omit molecules that have no hydrogens. For TZ, these numbers change to 14-37% for jun, and they remain 8-24% for jul. For QZ, the increases become 10-31% for jun and 8-23% for jul.