Q. First what is a Julian Date?
A. A Julian date has either 7 digits or 5 digits date and these are generally used in old IT legacy systems.
7 Digits – YYYYDDD – 2016092 (This is 1-Apr-2016. 92 means that this is 92nd day from 1-Jan in that year)
5 Digits – YYDDD – 16092
Q. What formulas to use to convert Excel Dates to Julian Dates?
A. For 7 Digits, use following formula
=TEXT(A1,"yyyy")&TEXT(A1-("1JAN"&YEAR(A1))+1,"000")
For 5 Digits, use following formula
=TEXT(A1,"yy")&TEXT(A1-("1JAN"&YEAR(A1))+1,"000")