Note

DF for total = DF for all factors + DF for all interactions + DF for error.

DF total = n - 1 where n is the total number of observations.

DF for factor = k - 1 where k is the number of the factor levels.

DF for Interaction = (k1 - 1) * (k2 -1) where k1 is the number of levels of factor one, and k2 is the number of levels of factor two. The same rule applies to interactions of more than two factors.