MTB: your solution, ="Days 1-" & TEXT(DATE(YEAR($R$3),MONTH($R$3)-1,0),"dd") & " (" & TEXT(DATE(YEAR($R$3),MONTH($R$3)-2,DAY($R$3)),"mmm yy") & ")" is just what was needed to display a calculated month and join it with text in a cell, and the result looks like this: Days 1-30 (Mar 06)
This is to create headings in 4 columns for 1-30 days, 31-60 days, 61-90 days and 91-120. These are just labels indicating how long a bill is overdue and they do not represent the number of calendar days.
Spiderman, thanks for your reply too.
Jerry