This article explains how to convert serial number dates to "Julian dates" and how to convert Julian dates to serial number dates in Microsoft Excel 2000. Julian dates refer to the number of days from the first of the year and the number of days until the end of the year as printed on most desktop calendars.
Many government agencies and contractors require the use of Julian dates.
Examples of Julian Dates
The following are examples of Julian dates:
Date Julian date ------------------------- Jan-01-1999 99001 Jan-10-1999 99010 back to the top Date Conversion Formulas
The following examples show how to work with serial number dates and Julian dates.To Convert a Serial Number Date to a Julian Date
Use the following Microsoft Excel 2000 formula to convert a serial number date to a Julian date
is the defined name that you gave to the cell that contains the date to be converted. You must enter the entire formula in a single cell.back to the top To Convert a Julian Date to a Serial Number Date
The following formula converts a Julian date to a standard serial number date in Excel (the formula assumes that your date is in the 20th century):
=DATE(1900+INT(Julian_Date/1000),1,MOD(Julian_Date,1000)) back to the top To Calculate the Number of Days Since January 1
To calculate the number of days since January 1 of the current year, use the following formula:
=INT(((NOW()/365.255)-(YEAR(NOW())-1900))*365.255) back to the top To Calculate the Number of Days Left in the Current Year
To calculate the number of days left in the current year, use thefollowing formula:
=(DATE(1+YEAR(NOW()),1,1)-(DATE(YEAR(NOW()),1,1)))- TRUNC(((NOW()/365.255)-(YEAR(NOW())-1900))*365.255) back to the top