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.
Dates and times in Excel are stored as serial numbers and converted to human readable values on the fly using number formats. When you enter a date in Excel, you can apply a number format to display that date as you like. In a similar way, the TEXT...
The TEXT function applies the number format you specify to a numeric value, and returns a result as text. In this case, the number format provided is "yyyymm", which joins a 4-digit year with a 2-digit month value. Display only option If you only...
This formula takes advantage of the fact that dates are just sequential numbers in Excel. It determines the last day of the previous year and subtracts that value from the original date with this formula: = B5 - DATE ( YEAR ( B5 ), 1 , 0 ) The...
The DATE function build dates from separate year, month, and day values. One of it's tricks is the ability to roll forward to correct dates when given days and months that are "out of range". For example, DATE returns April 9, 2016 with the...
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 given number format, as text. You can use the TEXT function to embed formatted numbers inside text.
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