In B1, enter =Average(A1:A$1)

Copy and paste it down B1 or use the fill handle.

"choo" wrote in message
...
Hello,
I want to calculate the average amount of a growing column A. Column A is
the amount and column B is the corresponding average of total column A
until
that row. How is the formula look like?

A B
2 2
3 2.5
1 2
5 2.75
4 3

Thank you.
choo