In C1:C10 enter numbers 1 to 10
In D1 enter =SUMIF(A:A,C1,B:B)
Copy this down to D10
I am assuming ID are 1 to 10
I you have loots of unknown ID's use a pivot table
--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email

"Amanda" wrote in message
...
Hi there,

I only have 2 columns in my dataset but i have around 40,000 rows so i
need
something relatively quick and easy! ID's are shown in column A and number
of
days is shown in column B, there are duplicate ID's in A. I need to sum B
according to column A (i.e. for ID: 1 i need to add B1 and B2 to equal
13).
Can anyone help me with this?

A B
1 5
1 8
2 4
3 6
3 5
3 2

Thanks,
--
Amanda