"Holly" wrote:
Is there a formula to convert the serial number 40899
above back to 12/22/2011?

It would help to know the context and the purpose.

If 40899 is the value of an Excel cell, you can simply change the format to
Date or some Custom date format.

But note that that only changes the appearance, not the value. That is
usually what we want. But if you want text in the form of a date, if 40899
is in A1, then in B1, enter the formula =TEXT(A1,"mm/dd/yyyy") or whatever
date format you want. Then copy B1, and paste-special-value into A1. You
can then delete B1.

There are similar things to do in VB. If that is your context, post a
response and we can provide details.