HOW TO FIND THE DAY OF THE WEEK

Instructions applicable for 1800 - 2199

Instructions

Example:
November 12, 2070

Step 1: Determine the code for the century:

Century:

1800ís

1900ís

2000ís

2100ís

Code #

2

0

6

4

Century = 2000ís
The code for 2000ís is
6

Total = 6

Step 2: Determine the code for the year:

Year:

00

04

08

12

16

20

24

28

32

36

40

44

48

52

56

60

64

68

72

76

80

84

88

92

96

 

Code #

1

6

4

2

0

5

3

Year = 70

68 is 2, so 69 is 3 and 70 is
4!

Total = 10 (6 + 4)

 

Step 3: Determine month code:

Jan = 6
Feb = 2
Mar = 2
Apr = 5
May = 0
Jun = 3
Jul = 5
Aug = 1
Sep = 4
Oct = 6
Nov = 2
Dec = 4

Month = November

November = 2

Total = 12 (6 + 4 + 2)

 

Step 4: Determine date code:

Date:

 

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

 

Code #

0

1

2

3

4

5

6

 

 

TIP:

Keep subtracting 7 or multiples from the totals, as you progress – to make it easier, instead of waiting till the end!  You may also use -1 or -2 for 6 or 5 etc. to reach the same result finally.

Date = 12

The code for date:12 is
5.

Total = 17(6 + 4 + 2 + 5)

Shortcut #1: Subtract 7, 14, 21 or 28, from the date to find code, dates less than 7 are already equal to the code.
Example:
Nov 12: 12 - 7 = 5.
Example:
Nov 26: 26 - 21 = 5

Shortcut #2: Simply add the date to the total. Example: Nov 12: Code=12, Total = 24 (6 + 4 + 2 + 12).

Step 5: Determine day-of-week from total

Divide the total from Step 3 by seven, the remainder giving the day-of-week:

Day-of-week:

Sun

Mon

Tue

Wed

Thu

Fri

Sat

Remainder:

0

1

2

3

4

5

6

Total = 17 (Century=6, Year=4, Month=2, Date=5)

17 divided by 7 is:
2 remainder 3

3 = Wednesday


Step 6: Donít forget leap-year!

Subtract 1 at any point in the process only if the year is a leap year provided the month is January or February – not for other months!

(Shortcut: As a last step, you can simply take the day before if the year is a leap year, and the month is Jan. or Feb.)

 

 

Leap-Year Rules

Since 1582 (1752 in USA and other years in other countries), the following is the currently widely-unknown leap-year rule:

A year is a leap-year if it is evenly divisible by 4 unless it is evenly divisible by 100, UNLESS it is evenly divisible by 400. This means that 1800, 1900, and 2100 are NOT leap years, but 2000 IS a leap year, since it is evenly divisible by 400!

2070 is not a leap year.

Shortcut #1: The year is a leap year if it is found in the table in step 1. (68 and 72 are leap years, but 70 is not)

Shortcut #2: A year is a leap year if it is evenly divisible by 4.


 

 

Code Quick Reference

Century:

1800ís

1900ís

2000ís

2100ís

Code #

2

0

6

4

 

Year:

00

04

08

12

16

20

24

28

32

36

40

44

48

52

56

60

64

68

72

76

80

84

88

92

96

 

Code #

1

6

4

2

0

5

3

Jan = 6
Feb = 2
Mar = 2
Apr = 5
May = 0
Jun = 3
Jul = 5
Aug = 1
Sep = 4
Oct = 6
Nov = 2
Dec = 4

 

Date:

 

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

 

Code #

0

1

2

3

4

5

6

Day-of-week:

Sun

Mon

Tue

Wed

Thu

Fri

Sat

Remainder:

0

1

2

3

4

5

6

(Courtesy: http://www.calendarhome.com/human)