Friday the 13th is considered unlucky because two different old superstitions merged: fear of the number 13 and fear of Friday as a day of misfortune. Over time, they combined into one famous belief. Here are the main reasons people give:
1️⃣ The number 13 was already seen as unlucky
In many Western traditions, 12 is viewed as a “complete” number (12 months, 12 zodiac signs, 12 hours on a clock).
Because 13 comes after 12, it was sometimes seen as irregular or disruptive.
There’s also a Christian tradition connected to The Last Supper:
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There were 13 people at the table.
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The next day, Jesus Christ was crucified.
This association helped reinforce the idea that 13 brings bad luck.
2️⃣ Friday historically had negative associations
In medieval Europe, Friday was sometimes seen as unlucky because several religious events were believed to have happened on that day, including the crucifixion of Jesus.
Because of this, people were sometimes wary of:
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starting journeys
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beginning important projects
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holding major events on Fridays.
3️⃣ A historical event that reinforced the myth
A famous story often linked to the superstition is the Arrest of the Knights Templar.
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On Friday, October 13, 1307, the French king ordered the mass arrest of members of the Knights Templar.
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Many were imprisoned or executed.
Some historians say this event may have helped strengthen the superstition.
4️⃣ Books and movies made it popular
The superstition became widely known in modern culture thanks to books and films like Friday the 13th, which turned the date into a famous horror theme.
✅ In short:
Friday the 13th is considered unlucky because two old fears—Friday and the number 13—combined over time, and stories, religion, and pop culture made the superstition spread.
Here are 5 weird things some people still do because of the superstition around Friday the 13th 😄
1️⃣ Buildings skip the 13th floor
Many hotels and office buildings don’t label a floor “13.”
Instead they go from 12 → 14.
This happens in many big cities like New York City and Toronto because developers worry that some guests or tenants might avoid the building.
2️⃣ People avoid flying
Some travelers refuse to book flights on Friday the 13th.
A few airlines even notice slightly lower bookings on that date because of superstition.
3️⃣ Hospitals sometimes schedule fewer surgeries
In some places, fewer people schedule elective (non-urgent) surgeries on that day because they think it’s unlucky.
Doctors say there’s no evidence the date affects outcomes—but the belief still affects decisions.
4️⃣ Businesses delay big decisions
Some companies avoid:
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launching products
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signing contracts
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starting construction
on Friday the 13th because of client superstition.
5️⃣ Some people stay home completely
A small number of people have an extreme fear of the date called Paraskevidekatriaphobia.
People with it may avoid:
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traveling
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going to school or work
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doing anything risky that day.
✅ Fun fact: Economists estimate superstition around Friday the 13th can cause millions of dollars in lost business because people cancel trips or postpone plans.
