EXHIBIT 11 PEOPLES BANCORP INC. AND SUBSIDIARIES COMPUTATION OF EARNINGS PER SHARE (dollars in thousands, except per share data) For the Three For the Nine Months Ended Months Ended September 30, September 30, 2005 2004 2005 2004 BASIC EARNINGS PER SHARE EARNINGS: Net income $5,268 $5,138 $15,259 $15,557 AVERAGE SHARES OUTSTANDING: Weighted average common shares outstanding 10,451,578 10,524,304 10,425,704 10,562,547 ---------------------------------------------------------------------------------------------------------------------- BASIC EARNINGS PER SHARE $0.50 $0.49 $1.46 $1.47 ---------------------------------------------------------------------------------------------------------------------- DILUTED EARNINGS PER SHARE EARNINGS: Net income $5,268 $5,138 $15,259 $15,557 AVERAGE SHARES OUTSTANDING: Weighted average common shares outstanding 10,451,578 10,524,304 10,425,704 10,562,547 Net effect of the assumed exercise of stock options based on the treasury stock method 139,892 145,494 138,049 185,517 ---------------------------------------------------------------------------------------------------------------------- Total weighted average diluted common shares 10,591,470 10,669,798 10,563,753 10,748,064 ---------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------------- DILUTED EARNINGS PER SHARE $0.50 $0.48 $1.44 $1.45 ----------------------------------------------------------------------------------------------------------------------