If you need to convert a date to a Julian date format in Excel, you can do so by building a formula that uses the TEXT, YEAR, and DATE functions.
"Julian date format" refers to a format where the year value of a date is combined with the "ordinal day for that year" (i.e. 14th day, 100th day, etc.) to form a date stamp.
There are several variations. A date in this format may include a 4-digit year (yyyy) or a two-digit year (yy) and the day number may or may not be padded with zeros to always use 3 digits. For example, for the date January 21, 2017, you might see:
1721// YYD201721//YYYYD2017021// YYYYDDD
For a two-digit year + a day number without padding use:
On the right side of the ampersand we need to figure out the day of year. We do this by subtracting the last day of the previous year from the date we are working with. Because dates are just serial numbers, this will give us the "nth" day of year.
To get the last day of year of the previous year, we use the DATE function. When you give DATE a year and month value, and a zero for day, you get the last day of the previous month. So:
If you need to convert a Julian date back to a regular date, you can use a formula that parses Julian date and runs it through the date function with a month of 1 and day equal to the "nth" day. For example, this would create a date from a yyyyddd Julian date like 1999143.
If you need to convert dates to text (i.e. date to string conversion) , you can use the TEXT function. The TEXT function can use patterns like "dd/mm/yyyy", "yyyy-mm-dd", etc. to convert a valid date to a text value. See table below for a list of...
To convert a normal Excel date into yyyymm format (e.g. 9/1/2017 > 201709), you can use the TEXT function. In the example shown, the formula in C6 is: = TEXT ( B6 , "yyyymm" ) How this formula works The TEXT function applies the number...
To get the nth day of year based on a given date, you can use a formula based on the DATE and YEAR functions. In the example shown, the formula in C5 is: = B4 - DATE ( YEAR ( B4 ), 1 , 0 ) With the date "June 1, 2016" in cell B4, the formula returns...
To get a real date from day number, or "nth day of year" you can use the DATE function. In the example shown, the formula in C5 is: = DATE ( 2015 , 1 , B5 ) How this formula works The DATE function build dates from separate year, month, and day...
The Excel DATE function creates a valid date from individual year, month, and day components. The DATE function is useful for assembling dates that need to change dynamically based on other values in a worksheet.
The Excel YEAR function returns the year component of a date as a 4-digit number. You can use the YEAR function to extract a year number from a date into a cell or to extract and feed a year value into another formula, like the...
The Excel TEXT function returns a number in a specified number format, as text. You can use the TEXT function to embed formatted numbers inside text.
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