EXHIBIT 12 IES UTILITIES INC. COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES Twelve Months Year Ended December 31, Ended 1992 1993 1994 1995 1996 September 30, 1997 (in thousands, except ratio of earnings to fixed charges) Net income $ 45,291 $ 67,970 $ 61,210 $ 59,278 $ 63,729 $ 69,736 Federal and state income taxes 20,723 37,963 37,966 41,095 43,092 46,843 Net income before income taxes 66,014 105,933 99,176 100,373 106,821 116,579 Interest on long-term debt 35,689 34,926 37,942 36,375 37,048 40,847 Other interest 3,939 5,243 3,630 8,085 6,666 7,966 Estimated interest component of rents 4,567 3,729 3,970 4,637 4,091 4,338 Fixed charges as defined 44,195 43,898 45,542 49,097 47,805 53,151 Earnings as defined $ 110,209 $ 149,831 $ 144,718 $ 149,470 $ 154,626 $ 169,730 Ratio of earnings to fixed charges (unaudited) 2.49 3.41 3.18 3.04 3.23 3.19 For the purposes of computation of these ratios (a) earnings have been calculated by adding fixed charges and federal and state income taxes to net income; (b) fixed charges consist of interest (including amortization of debt expense, premium and discount) on long-term and other debt and the estimated interest component of rents.