EXHIBIT 11 FIRST BELL BANCORP, INC. COMPUTATION OF PRIMARY AND FULLY DILUTED EARNINGS PER SHARE FOR THE NINE AND THREE MONTHS ENDED SEPTEMBER 30, 1999 (In Thousands, except per share amounts) (unaudited) Nine Months Ended September 30, 1999 Weighted Average Per Income Shares Share ------ ------ ----- Income available to common stockholders $5,943 5,701 -- Unearned ESOP shares -- (552) -- Unearned MRP shares -- (242) -- ------ ------- ------ Basic earnings per share 5,943 4,907 1.21 Effect of dilutive securities: MRP shares -- 65 -- Stock options -- 143 -- ------ ------- ------ Diluted earnings per share $5,943 5,115 $1.16 ====== ======= ====== Three Months Ended September 30, 1999 Weighted Average Per Income Shares Share ------ ------ ----- Income available to common stockholders 1,975 5,386 -- Unearned ESOP shares -- (543) -- Unearned MRP shares -- (242) -- ------ ------- Basic earnings per share 1,975 4,601 $0.43 ===== Effect of dilutive securities: MRP shares -- 65 -- Stock options 139 ------ ------- ------- $1,975 4,805 $0.41 ====== ======= =======