Insert Julian dates

The phrase "Julian date" is sometimes used to refer to a date format that is a combination of the current year, and the number of days since the beginning of the year. For example, January 1, 2007 is represented as 2007001 and December 31, 2007 is represented as 2003356. Note that this format is not based on the Julian calendar.

There is also a Julian date commonly used in astronomy, which is a serial date system starting on January 1, 4713 B.C.E.

Use the TEXT, TODAY, and DATEVALUE functions to do this task.

Worksheet example

The example may be easier to understand if you copy it to a blank worksheet.

Show How?

Create a blank workbook or worksheet.
Select the example in the Help topic. Do not select the row or column headers.

Selecting an example from Help
Press CTRL+C.
In the worksheet, select cell A1, and press CTRL+V.
To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Tools menu, point to Formula Auditing, and then click Formula Auditing Mode.

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A	B
Formula	Description (Result)
=TEXT(TODAY() ,"yy")&TEXT((TODAY() -DATEVALUE("1/1/"&TEXT(TODAY(),"yy"))+1),"000")	Current day in "Julian" format, with a two-digit year (Varies)
=TEXT(TODAY() ,"yyyy")&TEXT((TODAY() -DATEVALUE("1/1/"&TEXT(TODAY(),"yy"))+1),"000")	Current day in "Julian" format, with a four-digit year (Varies)

Notes

The current date used is taken from the computer's system clock.
In the formulas above, the year begins on January 1 (1/1). To convert the formulas to use a different starting date, edit the portion "1/1/" to the date you want.

Function details

DATEVALUE

TEXT

TODAY

Use the TEXT and DATEVALUE functions to do this task.

Worksheet example

The example may be easier to understand if you copy it to a blank worksheet.

Show How?

Create a blank workbook or worksheet.
Select the example in the Help topic. Do not select the row or column headers.

Selecting an example from Help
Press CTRL+C.
In the worksheet, select cell A1, and press CTRL+V.
To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Tools menu, point to Formula Auditing, and then click Formula Auditing Mode.

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A
Date
6/23/2007
Formula	Description (Result)
=TEXT(A2,"yy")&TEXT((A2-DATEVALUE("1/1/"&TEXT(A2,"yy"))+1),"000")	Date above in "Julian" format, with a two-digit year (07174)
=TEXT(A2,"yyyy")&TEXT((A2-DATEVALUE("1/1/"&TEXT(A2,"yy"))+1),"000")	Date above in "Julian" format, with a four-digit year (2007174)

Note In the formula above, the year begins on January 1 (1/1). To convert the formulas to use a different starting date, edit the portion "1/1/" to the date you want.

Function details

DATEVALUE

TEXT

This formula only works for dates after 3/1/1901, and in workbooks using the 1900 date system.

Worksheet example

The example may be easier to understand if you copy it to a blank worksheet.

Show How?

Create a blank workbook or worksheet.
Select the example in the Help topic. Do not select the row or column headers.

Selecting an example from Help
Press CTRL+C.
In the worksheet, select cell A1, and press CTRL+V.
To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Tools menu, point to Formula Auditing, and then click Formula Auditing Mode.

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2

A
Date
6/23/2007
Formula	Description (Result)
=A2+2415018.50	First date above in Julian date format used in astronomy (2454274.50)

Note To view the date as a number, select the cell and click Cells on the Format menu. Click the Number tab, and then click Number in the Category box.