If you have the account opening date in col A and 2/28/06 in cell B1, then a
formula such as this in cell b2 would be a starting point

=if($a2<=date(year($b$1),month($b$1),1),day($b$1), 1+$b$1-$a2)

"Beth" wrote:

Hello,

I have got a list of customer accounts in excel with the account opening
date listed.

I want to calculate the number of days interest I should charge each customer.

E.g. for February 2006;

If the account opened on 28th Feb then I would charge 1 days interest.

If the account opened on 1st Jan then I would charge 28 days interest for
February.

How can I calculate the number of days in a column?

Thank you in advance for your help,
Beth