EXHIBIT 11 SPARTECH CORPORATION AND SUBSIDIARIES STATEMENT RE COMPUTATION OF PER SHARE EARNINGS (In thousands, except per share data) QUARTER ENDED NINE MONTHS ENDED Aug. 1, Aug. 2, Aug. 1, Aug. 2 1998 1997 1998 1997 NET EARNINGS Basic and diluted net earnings $ 9,020 $ 6,731 $ 24,904 $ 18,885 WEIGHTED AVERAGE SHARES OUTSTANDING Basic weighted average common shares outstanding 27,102 26,403 26,775 26,387 Add: Shares issuable from assumed exercise of options 2,001 1,588 1,889 1,437 Diluted weighted average 29,103 27,991 28,664 27,824 shares outstanding NET EARNINGS PER COMMON SHARE Basic $ .33 $ .25 $ .93 $ .72 Diluted $ .31 $ .24 $ .87 $ .68