Excel recognizes only 15 significant figures.

No way to enter a 16 digit number without dropping the last digit and adding
a zero.

Unless you precede the 16 digits with an apostrophe.

But this becomes text and cannot be custom formatted as you wish.

In that case......after entering with apostrophe

Try a helper column with a formula.

=LEFT(H6,4) & "-" & MID(H6,5,4) & "-" & MID(H6,9,4)& "-" & RIGHT(H6,4)

When happy, select the helper column and Copy then paste
specialvaluesokesc

Delete the original column of text digits.


Gord Dibben MS Excel MVP

On Tue, 25 Aug 2009 15:47:07 -0700, JerryG
wrote:


I want to format 16 Digit CC#'s as 0000-0000-0000-0000. When I choose
Custom and enter it as I did above or using all # symbols
(####-####-####-####), it magically changes the last digit of the card # to a
zero. Any ideas what is causing this?

For Example:

9990090000092207 becomes 9990-0900-0009-2200

JerryG