Why the number 13 is considered unlucky

The number 13 has been viewed as unlucky for centuries, especially in Western cultures. One popular idea is that it disrupts the “perfect” completeness of 12—think 12 months in a year, 12 zodiac signs, and 12 apostles. Add one more, and it can feel a little… off.

This may be why some buildings skip the 13th floor, jumping straight from 12 to 14.

• 12 months in a year
• 12 zodiac signs
• 12 apostles

Why Fridays got a bad reputation

Fridays haven’t always enjoyed the best press. In medieval times, it was considered unlucky to start a journey or new project on a Friday. Some traditions even suggest that Eve gave Adam the fateful apple on a Friday, and in Christian belief, Jesus was crucified on a Friday, giving the day a somber association.

The “double whammy” of Friday + 13

Put Friday together with the number 13 and you get a combo many consider extra unlucky. The fear of this exact pairing even has a tongue-twister of a name: Friggatriskaidekaphobia (try saying that three times fast!).

How the superstition spread in the 20th century

The superstition really picked up steam in the 20th c.. Some credit Thomas Lawson’s 1907 novel Friday, the Thirteenth, where a shady stockbroker uses the date to crash the market. Then, the Friday the 13th horror movie franchise in the 1980s gave the date a pop-culture boost—complete with a hockey-mask-wearing villain named Jason.

Reality check: what really happens

Despite all the superstitions, most Friday the 13ths pass without any real disasters. For most people, it’s just another day—maybe with a dash of mystery or fun.

Key takeaway

Whether you avoid ladders and black cats or embrace the spooky vibes, Friday the 13th is a quirky reminder of how stories and traditions shape what we believe.