EXHIBIT 11.1 EXHIBIT 11.1 INPUT/OUTPUT, INC. COMPUTATION OF EARNINGS PER SHARE May 31, -------------------------- 1996 1995 ----------- ----------- Weighted average number of common shares outstanding 39,631,464 36,042,560 Dilutive effect of stock options 1,493,822 1,338,898 ----------- ----------- Weighted average number of common and common equivalent shares outstanding 41,125,286 37,381,458 Net earnings $38,677,000 $24,500,000 Earnings per common share - primary $ 0.94 $ 0.66 ----------- ----------- ----------- ----------- Weighted average number of common shares outstanding 39,631,464 36,042,560 Dilutive effect of stock options 1,622,075 1,353,446 ----------- ----------- Weighted average number of common and common equivalent shares outstanding 41,253,539 37,396,006 Net earnings $38,677,000 $24,500,000 Earnings per common share - fully diluted $ 0.94 $ 0.66 ----------- ----------- ----------- -----------