EXHIBIT 11 AIRGAS, INC. EARNINGS PER SHARE CALCULATIONS Three Months Ended Nine Months Ended December 31, December 31, (In thousands, except per share amounts) 2000 1999 2000 1999 ------------------ ----------------- Weighted Average Shares Outstanding: Basic shares outstanding 66,500 69,200 65,700 69,600 Stock options - incremental shares 700 1,000 500 1,100 Contingently issuable shares -- 600 800 300 ------ ------ ------ ------ Diluted shares outstanding 67,200 70,800 67,000 71,000 ====== ====== ====== ====== Net earnings $6,676 $9,760 $26,895 $37,757 ====== ====== ======= ======= Basic earnings per share $ .10 $ .14 $ .41 $ .54 Diluted earnings per share $ .10 $ .14 $ .40 $ .53