1 QUAKER STATE CORPORATION AND SUBSIDIARIES EXHIBIT 12 Statement re Computation of Ratio of Earnings to Fixed Charges FOR THE SIX MONTHS ENDED JUNE 30 (in thousands) 1998 1997 ===================================================================================================== Interest expense $ 14,514 $ 13,062 Interest factor of rental expense 4,637 4,567 --------------------------------- Total fixed charges $ 19,151 $ 17,629 ===================================================================================================== Income from continuing operations before income taxes $ 6,193 $ 22,588 Fixed charges 19,151 17,629 --------------------------------- Total earnings $ 25,344 $ 40,217 ===================================================================================================== Ratio of earnings to fixed charges 1.3 2.3 ===================================================================================================== (1) Interest factor of rental expense computed based on: (a) average interest factor from a sample of leases for operations representing in excess of 50% of rentals from continuing operations, and (b) one-third factor of rentals for other operations. 18