We present enumeration formulas for double circulant (DC) codes of length \(2m\) and four circulant (FC) codes of length \(4m\) over the finite field \(\mathbb {F}_q\) , with prescribed Euclidean hull dimension, assuming \(\gcd (m, q) = 1\) . These formulas significantly generalize previous results that were limited to special cases. In particular, we resolve an open problem posed by Zhu and Shi (J. Appl. Math. Comput. 68:1227–1244, 2022) concerning the case of reciprocal pair factors in the factorization of \(x^m - 1\) for the enumeration of self-dual and linear complementary dual (LCD) FC codes. Additionally, we correct an enumeration formula used in Zhu and Shi (Bull. Aust. Math. Soc. 98(1):159–166, 2018), leading to an improved bound on the relative distance for LCD FC codes.