EXHIBIT (12) ONEOK, Inc. Computation of Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividend Requirements For the Three Months Ended March 31, 2000 1999 - -------------------------------------------------------------------------------- (Thousands of Dollars) Fixed Charges, as defined Interest on long-term debt $ 16,220 $ 8,575 Other interest 5,151 3,559 Amortization of debt discount and expense 614 448 Interest on lease agreements 620 651 - -------------------------------------------------------------------------------- Total Fixed Charges 22,605 13,233 Preferred dividend requirements 14,960 15,039 - -------------------------------------------------------------------------------- Total fixed charges and preferred dividend requirements $ 37,565 $ 28,272 ================================================================================ Earnings before income taxes and income from equity investees $ 98,117 $ 99,168 Total fixed charges 22,605 13,233 - -------------------------------------------------------------------------------- Earnings available for combined fixed charges and preferred dividend requirements $ 120,722 $ 112,401 ================================================================================ Ratio of earnings to combined fixed charges and preferred dividend requirements 3.21x 3.98x ================================================================================ For purposes of computing the ratio of earnings to combined fixed charges and preferred dividend requirements, "earnings" consists of income before cumulative effect of a change in accounting principle plus fixed charges and income taxes, less undistributed income from equity investees. "Fixed charges" consists of interest charges, the amortization of debt discounts and issue costs and the representative interest portion of operating leases. "Preferred dividend requirements" consists of the pre-tax preferred dividend requirement. 1