## Find Day of the Week on Any Date

Lots of time we are in a situation where we are supposed to know the day on a particular date of the current year. Most of the methods you will come across are not mentally possible for everyone and hence not feasible. So find below a practical Quicker Maths method of finding what day of the week will be on a particular date.

Find the day on any date of current year

I have come across a very simple way to find the day of the week for any date of the current year. This idea is so easy, that most of you will wonder why you didn’t think of it yourselves.

Simple Day Calculation Trick

All you have to do is…….. Read More

## Which Day of the Week was My Birthday?

Find the answer to these questions instantly using the simple trick given below –

How to find the day of the week on which your birthday will fall next year?

or,

Which day of week was my birthday last year?

Today it is my birthday and somehow I was curious to know the day of the week on which I was born. Using Microsoft excel I found out that it was Thursday. I also tried listing the day of the week for all my birthdays till I will be 100 years old. I noticed a very simple but interesting facts about the days on which our birthday falls.

Every year the day advances by one day from previous year. For example I was born on 5th April 1984, Thursday. On my first birthday that is on 5yh April, 1985 it will be Friday.

But on every leap year it advances by 2 days. To understand this please refer the table below –

 Date Day 5-Apr-84 Thursday 5-Apr-85 Friday 5-Apr-86 Saturday 5-Apr-87 Sunday 5-Apr-88 Tuesday 5-Apr-89 Wednesday 5-Apr-90 Thursday 5-Apr-91 Friday 5-Apr-92 Sunday 5-Apr-93 Monday 5-Apr-94 Tuesday 5-Apr-95 Wednesday 5-Apr-96 Friday

As per the above table, you can see from year 1984 to 1987, every year the days were advancing by one day. But from 1987 to 1988 (leap), increased by 2 days. Then again it from 1988 to 1991 it increases by one day each year.

So with above logic, now if any one ask me what day was it on my last (2009) birthday, if this year (2010) my birthday is on Monday. It’s very simple, it was Sunday. And next year (2011) it will be Monday. After that (2012 – leap year) it will be Wednesday as on a leap year it will increase by 2 days.

If you have any special observation, please share below –

## Zeller’s Rule: Day on any date in the calendar

Zeller’s Rule : With this technique named after its founder Zeller, you can solve any ‘Dates and Calendars’ problems.

Zellers rule can be used to find the day on any particular date in the calendar in the history. All you have to know is the formula given below and how to use it.

Zeller’s Rule Formula:

F = K + [(13xM – 1)/5] + D + [D/4] + [C/4] – 2C

K = Date => for 25/3/2009, we take 25
In Zeller’s rule months start from march.
M = Month no. => Starts from March.
March = 1, April = 2, May = 3
Nov. = 9, Dec = 10, Jan = 11
Feb. = 12
D = Last two digits of the year, using previous year for January and February. Thus for 2009 = 09
C = The first two digits of century => for 2009 = 20

Example: 25/03/2009

F = 25 + [{(13 x1)- 1}/5] + 09 + 09/4 + 20/4 – (2 x 20)
= 25 + 12/5 + 09 + 09/4 + 20/4  – 2×20
=25+2+09+2+5-40 [ We will just consider the integral value and ignore the value after decimal]
= 43 – 40 =

Replace the number with the day using the information given below.
1 = Monday
2 = Tuesday
3 = Wednesday
4 = Thursday
5 = Friday
6 = Saturday
7 or 0 = Sunday

So it’s Wednesday on 25th march, 2009.

If the number is more than 7, divide the no. by 7. The remainder will give you the day.

I shall be very grateful if anyone of you can provide me the java script for this formula, so that I can post it here for everyone’s convenience.

Thanks in advance. I hope you will find the above method very useful.

you may find another post named, cyclicity very interesting.

Vineet Patawari – PGDM, ACA, B.COM (H)