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How to Find the Day of the Week for Any Date

Antique Pocketwatch
Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

What day did that happen? It’s easy to find the day of the week for births, weddings, deaths, and other historical events. Follow our simple instructions to calculate the day for any historical or future date—as far back as the mid-1700s.

For example, what day of the week was December 26, 2004, when the tsunami struck the Indian Ocean? Follow the example as you read along:

  1. Take the last two digits of the year.
  2. Add to that one–quarter of those two digits (discard any remainder).

  3. Add to that the day of the month and the Month Key number for that month:

    January = 1June = 5
    …leap year = 0July = 0
    February = 4August = 3
    …leap year = 3September = 6
    March = 4October = 1
    April = 0November = 4
    May = 2December = 6
  4. Divide the sum by 7. The remainder is the day of the week! One is Sunday, two is Monday, and so on. If there is no remainder, the day is Saturday. 
    [Note: At this step, it may be easiest to use long division to get the remainder. When using a calculator, after you divide the sum by 7, you’ll need to multiply the numbers after the decimal (not the whole number) in the result by 7 and then round to the nearest whole number to get the remainder.]

Note: 

  • If you’re searching for a week before 1900, add 2 to the sum before dividing; before 1800, add 4.
  • The formula doesn’t work for days before 1753.
  • From 2000 to 2099, subtract 1 from the sum before dividing.

Here’s an Example:

A tsunami occurred in the Indian Ocean on December 26, 2004.

Last two digits of year04
One-quarter of these two digits1
Given day of month:26
Key number for December6

Sum: 37

Because 2004 is in the range of 2000 to 2099, subtract 1 from 37. This yields 36.

36 divided by 7 = 5, with a remainder of 1. The tsunami took place on Sunday, the first day of the week.

Monday’s child is fair of face, 
Tuesday’s child is full of grace, 
Wednesday’s child is full of woe, 
Thursday’s child has far to go, 
Friday’s child is loving and giving, 
Saturday’s child works hard for a living, 
And the child that is born on the Sabbath Day, 
Is bonny and blithe and good and gay. 
–an old English nursery rhyme

Or… if you want to make it easy, check out our Day of the Week Calculator! It does the work for you!

Calendar

About The Author

Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana.

Read more from Catherine Boeckmann

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Comments

<span>Paul A Weir</span> Wed, 11/06/2024 - 19:10
I have found other errors.
<span>Aditi Dutta</span> Wed, 07/17/2024 - 11:42
When 6 is divided by 7, this is not the case 'no remainder' rather the remainder is 6 and as a result the answer will be Friday as required.
<span>Aditya Pratap Singh</span> Fri, 07/05/2024 - 00:45
Because its a century year Day 4. February 2000 4 3. 6. 0. 0 =4+3 will be seven and it will be zero because we don't count 7 .means only 6 days are there. Therefore the 6th day is Friday.
<span>Dante</span> Thu, 06/20/2024 - 08:19
lol i see now the remainder is 6... need to review that elementary school maths!
<span>Tino</span> Mon, 04/29/2024 - 15:00
Can you explain the month Key number. In your example Dec = 6, and in a comment Feb = 4 How are these calculated? Thanks
<span>Aditya Pratap Singh</span> Fri, 07/05/2024 - 00:48
There are codes for 12 months 1 4 4 0 2 5 0 3 6 1 4 6 And for leap year only code of January and February will be changed as 0 and 3
<span>Charlie</span> Thu, 05/02/2024 - 11:07
You have to trust that Jan = 1. For the next months, keeping adding the extra days past 28 (which when divided by 7 =0). So, 1 + 3 (for Jan.) = 4 for Feb. Then 4 + 0 (for Feb) = 4 for March... then 4 + 3 (for March) = 7 for April but 7 is 0 because there are 7 days in a week. Then 0 + 2 (for April) = 2 for May and so on.
<span>Kishan</span> Sun, 01/28/2024 - 19:58
And what id the one-quater is a decimal can you say an example with that?
<span>Kishan</span> Sat, 02/24/2024 - 05:12
Sorry my bad
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 01/29/2024 - 11:26

Hi, there,

Let’s try February 27, 1975.

1) Last two digits of the year are: 75

2) Add one-quarter of those two digits: 75/4 = 18.75.  We would discard anything past the decimal point, so just “18”

3) Add day of the month: 27

4) Add Month Key number for February: 4

5) Sum so far: 75 + 18 + 27 + 4 = 124

6) Because the year is between 1900 and 1999, we do not need to add or subtract anything before dividing.

7) Divide the sum by 7: 

For this division, we use the long division method to find the remainder. (Please forgive the rough formatting for long division.)

124/7 = 

    _17
7 | 124
      7
    --
      54
      49
      ---
        5

5 is the remainder. This corresponds to Thursday.

Hope this helps!