<p>Although a formula for the Alexander polynomials of some Celtic knots is already known, its complexity makes generalization difficult. This paper aims to find invariants that can be formulated for many more Celtic knots, and succeeds in providing formulas for their determinants and Goeritz invariants. Moreover, we present a conjecture generalizing this determinant formula, which is verified to be true in some cases using the symmetry of the Celtic knot, and approximately true in some further cases by computer simulation.</p>