well as long as all of the cells stay in the same spot you can still use the sum function, but it looks a little different (kinda likewhat jaclaz said.) =SUM(Jan!I11,Feb!I11, Mar!I11, Apr!I11, May!I11, Jun!I11, Jul!I11, Aug!I11, Sep!I11, Oct!I11, Nov!I11, Dec!I11)