Friday the 13th Survival Calculator

Why is Friday the 13th considered unlucky?

Friday the 13th is widely regarded as the unluckiest day in Western superstition, combining two independently ominous symbols: Friday (historically associated with bad luck and executions) and the number 13 (considered cursed in many cultures, so much so that many buildings skip the 13th floor entirely). The phobia even has a name — paraskevidekatriaphobia — and surveys suggest millions of people modify their behavior on these days, avoiding travel, signing contracts, or starting new projects.

Despite the reputation, Friday the 13ths are more common than most people realize. In any given year there are at least one and at most three of them, and the Gregorian calendar guarantees the 13th falls on a Friday more frequently than any other day of the week. A person who lives to age 80 will have encountered roughly 170 of them.

How does this calculator work?

The calculator starts at your birthday and steps through every calendar month up to today. For each month it checks whether the 13th falls on a Friday. Every match — from your birthday forward through yesterday — counts as one you've survived. The "next upcoming" result looks forward the same way, finding the first Friday the 13th still in your future.

Fun facts about Friday the 13th

• Every year has at least one. The calendar guarantees a minimum of one Friday the 13th every year.
• At most three per year. 1998, 2009, and 2015 each had three — in February, March, and November.
• The 13th is actually more often a Friday. Over a 400-year Gregorian cycle, the 13th lands on a Friday 688 times — more than any other weekday.
• The longest gap is 14 months. You'll never go more than 14 months without encountering one.
• Fear has a name. The clinical term for fear of Friday the 13th is paraskevidekatriaphobia, from the Greek words for Friday (paraskevi) and thirteen (dekatria).
• The film franchise made it iconic. The Friday the 13th horror film series, starting in 1980, cemented the date's place in pop culture.