9
1
I consider 7 days to be a week,
so if I look at 1 January 2019 - 7 January 2019,
I would say that is 7 days.
But often I seen when people are calculating the number of days between two dates or age they use the formula B1-A1
where A1
is the Start Date/DoB
and B1
is the end date or today's date.
This would give 6 for the above example.
I use (B1-A1)+1
which gives 7
and for dates of birth I would use ((B1-A1)+1)/365.25
.
Which is correct?
27 - 1 is 6, no? What is correct depends on your definition and whether you include timestamps or not. When subtracting 20190101T00:00:00 from 20190107T23:59:59, you get 6.999, which can be rounded appropriately. – slhck – 2019-03-25T12:38:42.640
@slhck That really makes sense when you think about the time as well as date. – Naz – 2019-03-25T12:54:00.757
7If start date/dob and today are the same day, do you want the answer to be 0 or 1? B1-A1 is the number of complete days that have past. – Forward Ed – 2019-03-25T13:28:28.387
2You're asking whether exclusive or inclusive operations are correct. They're both correct, depending on what you are trying to achieve. See @Chris Rogers's answer below. – studog – 2019-03-25T18:56:32.783
(1) Well, there’s also the point of view that there are 5 days *between* 1 January and 7 January. See this. (2) If a person was born on 27 March 1959, on what day did they turn 20? 27 March 1979. Now, if
– Scott – 2019-03-27T05:14:55.970B1
= 27 March 1979 andA1
= 27 March 1959, what does your formula say? What does it say forB1
= 26 March 1979?