Excel doesn't like dates before 1900.

So those entries that look like dates (but are before 1900) aren't really dates.

You may be able to use:

=if(isnumber(a1),text(a1,"yyyymmdd"),someotherexpr ession)

But that other expression would depend on how those text entries looked.

Some combination of =mid(), =right() and/or =left() may do it for you.

12/25/1850
could be
=IF(ISNUMBER(A1),TEXT(A1,"yyyymmdd"),MID(A1,7,4)&L EFT(A1,2)&MID(A1,4,2))


- Butch wrote:

I tried formatting with a created "Custom" format of "yyyy-mm-dd" and
that works EXCEPT, it doesn't affect dates before 1900. Why wouldn't it,
and how can I get it to affect all dates?

--

Dave Peterson