Exhibit 11 THERMO INSTRUMENT SYSTEMS INC. Computation of Earnings per Share Three Months Ended ----------------------------- June 28, June 29, 1997 1996 ------------------------------------------------------------------------ Computation of Fully Diluted Earnings per Share: Income: Net income $ 37,219,000 $ 35,296,000 Add: Convertible obligation interest, net of tax 2,021,000 1,055,000 ------------ ------------ Income applicable to common stock assuming full dilution (a) $ 39,240,000 $ 36,351,000 ------------ ------------ Shares: Weighted average shares outstanding 97,221,904 95,073,737 Add: Shares issuable from assumed conversion of convertible obligations 13,353,222 11,281,008 Shares issuable from assumed exercise of options (as determined by the application of the treasury stock method) 855,492 1,047,598 ------------ ------------ Weighted average shares outstanding, as adjusted (b) 111,430,618 107,402,343 ------------ ------------ Fully Diluted Earnings per Share (a)/(b) $ .35 $ .34 ============ ============ PAGE Exhibit 11 THERMO INSTRUMENT SYSTEMS INC. Computation of Earnings per Share Six Months Ended ----------------------------- June 28, June 29, 1997 1996 ------------------------------------------------------------------------ Computation of Fully Diluted Earnings per Share: Income: Net income $ 70,806,000 $ 69,339,000 Add: Convertible obligation interest, net of tax 4,051,000 2,404,000 ------------ ------------ Income applicable to common stock assuming full dilution (a) $ 74,857,000 $ 71,743,000 ------------ ------------ Shares: Weighted average shares outstanding 97,146,214 93,474,351 Add: Shares issuable from assumed conversion of convertible obligations 13,407,687 12,863,360 Shares issuable from assumed exercise of options (as determined by the application of the treasury stock method) 882,359 1,047,598 ------------ ------------ Weighted average shares outstanding, as adjusted (b) 111,436,260 107,385,309 ------------ ------------ Fully Diluted Earnings per Share (a)/(b) $ .67 $ .67 ============ ============