Exhibit 11 THERMEDICS Computation of Earnings per Share Three Months Ended Nine Months Ended ------------------------ ------------------------ Sept. 28, Sept. 30, Sept. 28, Sept. 30, 1996 1995 1996 1995 ----------------------------------------------------------------------------- Computation of Primary Earnings per Share: Net Income (a) $ 5,767,000 $ 4,017,000 $19,694,000 $10,945,000 ----------- ----------- ----------- ----------- Shares: Weighted average shares outstanding 36,645,979 33,770,265 36,333,577 33,564,187 Add: Shares issuable from assumed exercise of options (as determined by the application of the treasury stock method) 437,281 - 470,830 - Shares issuable from assumed conversion of subordinated convertible debentures 1,988,984 - 968,993 - ----------- ----------- ----------- ----------- Weighted average shares outstanding, as adjusted (b) 39,072,244 33,770,265 37,773,400 33,564,187 ----------- ----------- ----------- ----------- Primary Earnings per Share (a) / (b) $ .15 $ .12 $ .52 $ .33 =========== =========== =========== ===========