The poor, ignored, hardly supported DATEDIF function

[jdellasala]

I don't remember how, but a couple of years back I discovered the DATEDIF function.
You won't find it Excel's Functions lists, when you type "=DATEDIF" TAB will not add a opening parenthesis, and provides no parameter information. Yet, when you type "=DATEDIF(" with the opening parenthesis, it will appear in the Tool Tip, and you can click on the Tool Tip name to get the function's help!

It's even on the Microsoft Support site!
I THINK it is a holdover from Lotus 123 compatibility, but don't know for sure. However, I really like this function, and it provides information that is otherwise more cumbersome to get:

Book1
	A	B	C
1	01/01/2021	12/18/2022	DATEDIF( start_date, end_date, unit )
2	Parameter	Value	Meaning
3	Y	1	The number of complete years in the period.
4	M	23	The number of complete months in the period.
5	D	716	The number of days in the period.
6	MD	17	The difference between the days in start_date and end_date. The months and years of the dates are ignored. Important: We don't recommend using the "MD" argument, as there are known limitations with it. See the known issues section below.
7	YM	11	The difference between the months in start_date and end_date. The days and years of the dates are ignored
8	YD	351	The difference between the days of start_date and end_date. The years of the dates are ignored.
Sheet1

Cell Formulas
Range	Formula
B1	B1	=TODAY()
B3:B8	B3	=DATEDIF($A$1,$B$1,A3)

With it, you can easily do fun stuff like this:

Book1
	D	E
12	09/07/1973	You are 17,999 days old!
13	12/18/2022	That is 49 Years, 3 Months, 11 Days Old!
Sheet1

Cell Formulas
Range	Formula
E12	E12	="You are "&TEXT(DATEDIF(D12,D13,"D"),"#,###")&" days old!"
D13	D13	=TODAY()
E13	E13	="That is "&DATEDIF(D12,D13,"Y")&" Years, "&DATEDIF(D12,D13,"YM")&" Months, "&DATEDIF(D12,D13,"MD")&" Days Old!"

And no, that is not my birthday.

Anyone else familiar with this function? Know about its history or why it's not officially supported?

 

[GraH]

On another post, there is this reaction. Post in thread 'Datedif Function not accurate' Datedif Function not accurate

 

[jdellasala]

On another post, there is this reaction. Post in thread 'Datedif Function not accurate' Datedif Function not accurate

The subject isn't true. The difference between two dates 365 days APART is always one less than the number of days because it's calculating the difference between the two numbers, not counting the number of items between the two dates including both dates. Effectively, the subtraction starts counting at 10/2/2020.
That's pretty commonly known, and needs to be compensated for as needed whether needed for simple subtraction of the start date from the end date, or using DATEDIF, or even the DAYS function! The only place I see it kind of work is in the formula

=SEQUENCE(365,,DATEVALUE("10/1/2020"))

which returns a column of dates from 10/1/2020 to 9/30/2021.
The "Known issues" relates only to using the "MD" option, and only under specific circumstances.

 

[GraH]

The link was supposed to bring you directly to the reaction of Peter_SSs , with a link to some Microsoft information.

 

[jdellasala]

The link was supposed to bring you directly to the reaction of Peter_SSs , with a link to some Microsoft information.

The link in the article is the same one I have above, and only reports the potential inaccuracy of the MD parameter. It is nearly identical to the information in the Excel help.

 

[GraH]

Simply overlooked there was a link in your first post. Since Peters' link clearly states it is about Lotus 123, I never expected you reference to the same.
In a professional context, I never needed such a function. However for aging of customer tickets, open orders, project Running, etc it might be handy as it reads better then say 4563 days open. Now that's a long time