Exhibit 11 ENGINEERED SUPPORT SYSTEMS, INC. STATEMENT RE: COMPUTATION OF EARNINGS PER SHARE Three Months Ended Six Months Ended April 30 April 30 ---------------------------- ---------------------------- 2000 1999 2000 1999 ---------- ---------- ---------- ---------- NET INCOME $2,570,099 $1,792,234 $5,144,370 $3,180,636 ========== ========== ========== ========== BASIC EARNINGS PER SHARE Average basic shares outstanding 6,984,016 5,052,423 6,953,217 4,950,724 ========== ========== ========== ========== $.37 $.35 $.74 $.64 ========== ========== ========== ========== DILUTED EARNINGS PER SHARE Average basic shares outstanding 6,984,016 5,052,423 6,953,217 4,950,724 Net effect of dilutive stock options<F1> 177,078 178,179 163,470 179,103 ---------- ---------- ---------- ---------- 7,161,094 5,230,602 7,116,687 5,129,827 ========== ========== ========== ========== $.36 $.34 $.72 $.62 ========== ========== ========== ========== <FN> <F1> Based on the treasury stock method.