EXHIBIT 11 AIRGAS, INC. EARNINGS PER SHARE CALCULATIONS Three Months Ended Six Months Ended September 30, September 30, (In thousands, except per share amounts) 2000 1999 2000 1999 Weighted Average Shares Outstanding: Basic shares outstanding 65,400 69,700 65,200 69,800 Stock options - incremental shares 400 1,300 400 1,200 Contingently issuable shares 800 200 1,300 200 ------ ------ ------ ------ Diluted shares outstanding 66,600 71,200 66,900 71,200 ====== ====== ====== ====== Net earnings $10,403 $18,912 $20,219 $27,997 ====== ====== ====== ====== Basic earnings per share $ .16 $ .27 $ .31 $ .40 Diluted earnings per share $ .16 $ .27 $ .30 $ .39