DOB Formula?

[smudge]

Some years ago, I had a simple calculated formula of how to work out from a date of birth, which actual day of the week a person was born on.

I just can't remember it, so wondered if any of you could jog my memory please.

[Clanad]

Until you find the formula, look here...

http://fp.ayrshireroots.plus.com/Genealogy/Reference/Day%20Born%20z.htm

[smudge]

Hi Clanad - Thank you for your expeditious response! I've just used that site & it came up with a Saturday, which I know is the day I was born on. (Works hard for a living)!

 

I've been searching high & low for my formula, but it must have got lost along with my address book, last year. At least in the meantime, I can now work out all the days my relatives were born on. I've been working on my family tree & it's just nice to know that too. Thanks again.

[THECORBYLOON]

Smudge I used to work with a guy who could do this sort of thing in his head and he could work out the date if you telt him the day of the week. Anyway I've found this

The following formula - named Zeller's Rule - allows you to calculate a day of the week for any date: F = k + [(13 x m-1)/5] + D + [D/4] + [C/4] - 2 x C
k is the day of the month. Let's use January 27, 2024 as an example. For this date, k = 27.
m is the month number. Months have to be counted specially: March is 1, April is 2, and so on to February, which is 12 (this makes the formula simpler, because on leap years February 29 is counted as the last day of the year). Because of this rule, January and February are always counted as the 11th and 12th months of the previous year. In our example, m = 11.
D is the last two digits of the year. Because of the month numbering, D = 23 in our example, even though we are using a date from 2024.
C stands for century: it's the first two digits of the year. In our case, C = 20.

Now let's substitute our example numbers into the formula:
F = k + [(13 x m-1)/5] + D + [D/4] + [C/4] - 2 x C
= 27 + [(13 x 11-1)/5] + 23 + [23/4] + [20/4] - 2 x 20
= 27 + [28.4] + 23 + [5.75] + [5] - 40
[drop every number after the decimal point]
= 27 + 28 + 23 + 5 + 5 - 40 = 48.
Once we have found F, we divide it by 7 and take the remainder (if the remainder is negative, add 7). A remainder of 0 corresponds to Sunday, 1 means Monday, etc. For our example, 48 / 7 = 6, remainder 6,
= SATURDAY

[SteveD]

I bet I'm not the only one who checked that with Clanad's link!

[Phantaxus]

The one I am thinking of is in the book "rapid maths tips and tricks" and is possible to calculate in your head but I willl need to find my copy when I get home

[smudge]

Everyone - Thank you so much for all your help.

It was a fella at work who gave me the formula too. I will print off this page & work on CORBYLOON's formula. Thank you.

[smudge]

Phantaxus -  That might be an interesting little book to keep at hand.

[Tweed]

this has been answered before

http://www.theanswerbank.co.uk/People_and_Places/Questio n76417.html

[smudge]

Hi Tweed - thanks, but that link gives me 'The page you asked cannot be found'.

[Tweed]

you have to remove the </P> from the end of the URL http://www.theanswerbank.co.uk/People_and_Places/Question76417.html

[smudge]

Thanks Tweed - I just looked that up. I must have been away that week. Very useful.

[maitre d']

Smudge - far easier to use excel -  type in the date eg 22nd Dec 1960 is entered as 22/12/60, highlight the cell/column, got to Fornat, Cells, Number tab, highlight "Custom" in the rhs type box enter dddd:dd:mmm:yyyy.  Thursday 22nd December 1960.  
 

[maitre d']

smudge - sorry you should enter the year in full ie 1960

[smudge]

Thanks maitre d' - this gets even better & I do like a challenge! :0)