"Aladin Akyurek" wrote...
Make sure that the dates are true dates, not just looking as dates. A
diganostic test would be:

=COUNT(DateRange)=SUMPRODUCT(ISNUMBER(DateRange+0 )+0)
....

If we're talking dates pasted from HTML tables with leading or trailing
nonbreaking spaces (decimal char code 160), adding 0 to them will return
errors, in which case your COUNT and SUMPRODUCT calls would return the same
values.

More robust to use the array formula

=COUNT(DataRange)=COUNT(-SUBSTITUTE(DateRange,CHAR(160),""))