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Why is Thirteen considered Unlucky

Subject: Blog Posts

Description: The number thirteen is a significant number but has gathered a certain amount of bad publicity over the years. Why is this? What is Special about the number thirteen and why is it considered unlucky?

Posted by David Caldwell on 10/11/13 at 21:32

The Number 13

The number thirteen is a significant number but has gathered a certain amount of bad publicity over the years.  Why is this?  What is Special about the number thirteen and why is it considered unlucky?

Positive Connections

Thirteen is a prime number it is only divisible by one and itself,

Thirteen is a bakers or devils dozen, this probably originated as ‘one for luck’ in case a loaf was ruined then the total number of products could still be divisible.

Thirteen is a Fibonacci number 0, 1, 1, 2, 3, 5, 8, and 13

In English thirteen is the first connective number which is a combination of three and teen, whereas twelve and all numbers below have a unique name.

In a deck of cards there are 13 cards in a suit.

Women have thirteen menstrual cycles in a year.

Some people believe that the moon has 13 Lunation’s a year, though some make this to be 12.

There are thirteen Archimedean solids.

Metatron’s Cube has thirteen nodes, the joining of each node maps out the five Platonic Solids, star tetrahedron, hexahedron, octahedron, dodecahedron and icosahedron.


Ancient Egyptians believed that there were thirteen steps on the ladder to eternity.

Negative Connections

Friday 13th

If the date is the 13th and they day is Friday then the resulting Friday the 13th makes the day unlucky, it has been proven that there is less traffic on the roads on Friday the 13th presumably due to people being afraid to drive on that day.

There are however negative connections and this has given rise to the number being considered ill-fated by the superstitious.   There is even a word for fear of the number thirteen, Triskaidekaphobia.

In the New Testament the Last Supper is attended by thirteen individuals, the twelve apostles and Jesus.

In the biblical book of Genesis 13 is cited to be the number of rebellion. 

In Viking mythology they believed that if 13 sat down at a banquet then the thirteenth uninvited guest would be Loki.

12 was considered a perfect number, there was twelve months in a year, 12 apostles and 12 tribes of Israel, one more than perfection was considered to be evil.

It was believed that there were 13 knots on the hangman’s noose

Sailors thought it was unlucky to set sail on a boat with thirteen crew members as one would meet with a fatal accident.

There are traditionally 13 Witches in a Coven.

It was considered unlucky for thirteen diners to sit at a table as it was believed that the thirteenth to rise was to die within the year so rather than take the risk it the thirteenth got banished to a side table.

Another take on the above was if 13 people meet in a room then one is to die within the year.

An individual who has 13 letters in their name is considered to be doomed to having the devil’s luck.  I have 13 letters in my name but is it so bad to have the Devil’s luck?  He seems to have done quite well.

The unlucky reputation of number thirteen pervades our culture, it is common to find a building without a thirteenth floor,  hotels without a room number 13 and new housing developments are numbered to avoid the number as well as numbers  four and nine as these are considered unlucky by the Chinese (4 + 9 = 13!).  The decision by developers to exclude those numbers may well be financial as houses numbered 13 sell for less than other dwellings.

In France rather than name a building 13, they name the house twelve ‘bis’ or twelve twice.

It may be unwise to ignore number 13 as you are creating an entity that can exist between the gaps where there is a house, a floor or a room that is numbered 13 but not in our reality.


Keywords: Friday 13th, 13, thirteen, unlucky, number