By definition, NK0(R) is K0(R[t]) modulo K0(R). We give a formula for this group when R is of finite type over a field of characteristic zero. The group is bigraded and determined by its typical pieces, which are the cdh cohomology groups Hp (R, Ωp). We also partially answer a question of Bass by proving that if NK0(R) and NKn(R) vanish for all negative n then K0(R) = K0(R[t, u, v, ..., z]).