EXHIBIT 11 AIRGAS, INC. EARNINGS PER SHARE CALCULATIONS Three Months Ended Six Months Ended September 30, September 30, (In thousands, except per share amounts) 2001 2000 2001 2000 ------------------ ---------------- Weighted Average Shares Outstanding: - ----------------------------------- Basic shares outstanding 67,900 65,400 67,600 65,200 Stock options and warrants - incremental shares 1,600 400 1,300 400 Contingently issuable shares -- 800 -- 1,300 ------ ------ ------ ------ Diluted shares outstanding 69,500 66,600 68,900 66,900 ====== ====== ====== ====== Net earnings (loss) $14,553 $10,403 $(30,996) $20,219 ====== ====== ====== ====== Basic earnings per share: - ------------------------ Earnings per share before the cumulative effect of a change in accounting principle $ .21 $ .16 $ .41 $ .31 Cumulative effect per share of a change in accounting principle -- -- (.87) -- ------ ------ ------ ------ Net earnings (loss) per share $ .21 $ .16 $ (.46) $ .31 ====== ====== ====== ====== Diluted earnings per share: - -------------------------- Earnings per share before the cumulative effect of a change in accounting principle $ .21 $ .16 $ .41 $ .30 Cumulative effect per share of a change in accounting principle -- -- (.87) -- ------ ------ ------ ------ Net earnings (loss) per share $ .21 $ .16 $ (.46) $ .30 ====== ====== ====== ====== Pro forma amounts assuming the application of the change in accounting principle (adoption of SFAS 142) applied retroactively: - -------------------------------- Net earnings $14,553 $13,947 $28,004 $27,323 ====== ====== ====== ====== Basic earnings per share $ .21 $ .21 $ .41 $ .42 ====== ====== ====== ====== Diluted earnings per share $ .21 $ .21 $ .41 $ .41 ====== ====== ====== ======