Why Is the Number 13 Considered Unlucky?

With so many numbers to choose from, it seems pretty unlucky that 13 has received the brunt of superstitious fear.

For some, the unfortunate history that has followed the number 13 is no more than a silly myth, but for many, it's to be avoided at all costs, especially in casinos.

But, where did triskaidekaphobia (it's real, we've checled) originate from? Is there any truth to it? Or is it simply a meme that’s gone on too long?

Here is a brief history.

The 13th guest

The most commonly accepted reason why the number 13 has garnered such a bad wrap is rooted in religious beliefs.

At "The Last Supper", Jesus and 11 of his disciples were all having a fantastic time until the final and 13th guest entered the room – Judas, and we all know how that turned out.

Similarly, an ancient Norse lore maintains that evil did not exist until the appearance of the mischievous God, Loki. He was the 13th guest at a dinner party in Valhalla and brought with him chaos and destruction.

A perfect number

Just like competitive siblings, it seems 13 lost out to it’s younger and more talented brother: 12.

In ancient times, the number 12 was considered so perfect that the ancient Sumerians used it as the basis of the numeral system we use today.

There are 12 months in a year, two 12-hours in a day and 12 inches in a foot. It’s no wonder that 13 seemed like the weird, unusual sibling by comparison.

The Thirteen Club

Established in the USA during the 19th century, The Thirteen Club was created to debunk popular superstitious myths, particularly inspired by the “13 round a table” superstition.

On the 13th of each month, 13 members would sit around a table and break mirrors, walk under ladders and were forbidden from throwing salt over their shoulder – all while recording how many of its 400 person strong society died within the year.

Unsurprisingly, no one died and it was reported that, in fact, “the members during the past twelve months have been exceptionally healthy and fortunate.”

Shocking.

Bye bye number 13

Despite no one dying in The Thirteen Club and there being no substantial evidence that the number 13 is cursed, it hasn’t stopped us from building skyscrapers sans 13th floors, omitting 13 from hotels, hospitals and airports, or avoiding travelling on Friday 13th altogether.

In fact, if you’re looking to jet off on a budget, Friday 13th might be the perfect day as plane tickets are considerably cheaper.

This modern-day desire to avoid the number 13 results in a financial loss of around $800 million (USD) every year.

With people avoiding travelling, getting married and even going to work, this annual financial drop is a reminder that if enough people believe something – it doesn’t matter what the truth is.

Unlucky numbers around the world

Bingo lingo might refer to it as "unlucky for some", but the number 13 is not a worldwide phenomenon. It’s a Western construct that’s mainly popular in the UK and USA.

Fear not, however, as there are plenty of other superstitious numbers across the globe for us to look at.

China: 4

Just like the number 13 being left out of building plans, you’re unlikely to find the number 4 in an elevator in China, or anywhere for that matter.

In Cantonese, the word ‘four’ sounds similar to the word ‘death’ which has resulted in its exile from Chinese society.

In Hong Kong, because of the blend of East Asian and Western culture, some buildings omit the 13th floor along with all the floors with 4s. That's a lot of missing floors. 

However, the number 54 is spared the boot because it means “shall live forever and will not die” – naturally.

Italy: 17

In Italian culture, the number 17 is considered unlucky. Why? In Roman numerals, XVII is an anagram of VIXI, which is Latin for “I lived” or in other words “My life is over”.

It’s also common to see this on Roman tombstones, which only strengthens the 'unlucky' argument for the Italians.

USA: 191

You’re likely to still find the 191st floor of a skyscraper, but when it comes to US aviation, 191 is an unlucky number.

Since 1967, there have been five separate flights with the flight number 191 that have resulted in tragedy or near tragedy.

The most deadly was in 1979 when American Airlines Flight 191 crashed at Chicago’s O’Hare Airport, killing all passengers and crew on board as well as two people on the ground.

More recently in 2012, a JetBlue Airways Flight 191 to Las Vegas diverted to Texas after the captain had an alleged panic attack. He was locked out of the of the cockpit by the First Officer and restrained by passengers.

Fortunately, no one was harmed but it's unsurprising that flight 191 has been retired by several airlines.

Is Friday the 13th actually unlucky?

The short and most rational answer – no. Numbers are arbitrary and have no bearing on the events of earthly events.

In 1993, however, a British Medical Journal study claimed there was a “significant” increase in incidences on Friday 13th.

However, the author later confessed that it was just “a bit of fun” and the study was a spoof, as is tradition in the Christmas edition.

Igor Radun from the University of Helsinki's Institute of Behavioural Sciences in Finland says: "There are no lucky or unlucky numbers; they exist only in our heads – or in the heads of some of us – and they might become lucky or unlucky only if we make them as such."

If any research is to be considered, a 2008 Dutch study found that people are actually less likely to be injured on Friday 13th.

The research found that not only did fewer traffic accidents happen on Friday the 13th than other Fridays but reports of fire and theft also dropped.

So, whether you vow never to play 13 slot games in a row or call 13 your lucky number, remember that a number is just a number and 13 is no different – scientifically speaking.

More on luck and probability

Discover our other articles about luck.

• Find out the easiest UK lottery to win
• Be amazed by 10 Unlikely Events That Actually Happened
• See the full results of our Perception of Probability Survey
• View our Britain at Odds Infographic
• View our Hazard Perceptions Infographic
• Learn more about The Perception of Probability

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