Question: how do you calculate julian date in excel?
Answer: If you want to convert calendar date to Julian date, you can use below formulas. In a blank cell, type this formula =TEXT(A1,"yy")&TEXT((A1-DATEVALUE("1/1/"&TEXT(A1,"yy"))+1),"000") and press Enter key, if you need you can apply this formula to a range by dragging the auto fill handle.