I would like to be able to find the sum of a range of cells if a
corresponding cell in a different column but the same row has a certain
letter.

For example, The cell I want the formula in is L39. The cells in column (I)
have a lable of either C or P as the first letter. The cells in column (K)
have a certain number value. I would like to find the sum in the range of
cells in column K in which the corresponding cell number in Column (I) has
the first letter of C. Thus, if I12=C, I13=C, I14=P, and K12=2, K13=3,
K14=4, then the sum of K12:K14 would be 5.

how can i do this?

eric

Hi Eric,

Have a go with sumif() function :

SUMIF(range,criteria,sum_range)

HTH
Carim

=SUMIF(I12:J14,"C",J12:J14)