EXHIBIT 11 - STATEMENT OF COMPUTATION OF EARNINGS PER SHARE TOMPKINS COUNTY TRUSTCO INC. WEIGHTED AVERAGE SHARES FOR 1997 BASIC WEIGHTED ACTUAL NO. AGGREGATE AVERAGE DATE DESCRIPTION SHARES DAYS SHARES SHARES 01-Jan-97 Director's Fees 299 Treasury Shares 3,294,262 55 181,184,410 3,294,262 25-Feb-97 118 shares of I.S.O.P. allocated 3,294,380 35 115,303,300 3,294,308 01-Apr-97 Director's Fees 312 Treasury Shares 3,294,692 14 46,125,688 3,294,360 15-Apr-97 428 shares issued Officer options exercised 3,295,120 29 95,558,480 3,294,525 14-May-97 Repurchased 80,000 shares 3,215,120 48 154,325,760 3,273,468 01-Jul-97 Director's Fees 286 Treasury Shares 3,215,406 92 295,817,352 3,253,901 01-Oct-97 Director's Fees 260 Treasury Shares 3,215,666 7 22,509,662 3,252,945 08-Oct-97 1,985 shares issued Officer options exercised 3,217,651 85 273,500,335 3,244,726 Number of days in the year: 365 1,184,324,987 3,244,726 1997 Net Income (Numerator) $9,855,594 Basic Weighted Average Shares (Denominator) 3,244,726 BASIC EARNINGS PER SHARE $3.04 1997 Net Income (Numerator) $9,855,594 Effect of dilutive securities (options) 37,610 Diluted Weighted Average Shares (Denominator) 3,282,336 DILUTED EARNINGS PER SHARE $3.00 19