Pi Day

Pi Day is an annual celebration of the mathematical constant π (pi), which represents the ratio of a circle’s circumference to its diameter. This number, approximately 3.14159, is celebrated on March 14th (3/14) due to the date’s resemblance to the first three digits of pi.

Quick Facts

When is it?: March 14th (3/14)
Tagged as: Mathematical holiday, Educational observance
What’s the hashtag?: #PiDay, #PiDaySF
When was it founded?: 1988
Who founded it?: Larry Shaw, a physicist at the San Francisco Exploratorium

History of Pi Day

Pi Day began in 1988 when physicist Larry Shaw organized the first celebration at the San Francisco Exploratorium. The event featured staff and visitors marching around a circular space and then enjoying fruit pies. What started as a small gathering has grown into an international celebration of mathematics.

In 2009, the U.S. House of Representatives officially recognized March 14 as National Pi Day, and in 2019, the United Nations also acknowledged it as an international celebration. Today, Pi Day is observed worldwide by math enthusiasts, educators, and students who use the occasion to engage with mathematics in fun and creative ways.

Timeline

1988: Larry Shaw organizes the first Pi Day celebration at the San Francisco Exploratorium
2009: The U.S. House of Representatives officially recognizes March 14 as National Pi Day
2015: “Super Pi Day” occurs on 3/14/15, representing the first five digits of pi
2017: Larry Shaw, known as the “Prince of π,” passes away
2019: The United Nations recognizes Pi Day internationally

Dates by Next Year (2025 to 2030)

Year	Month and Date	Day
2025	March 14	Friday
2026	March 14	Saturday
2027	March 14	Sunday
2028	March 14	Tuesday
2029	March 14	Wednesday
2030	March 14	Thursday

How Pi Day is Observed

Pi Day is celebrated in various ways around the world. Many people enjoy eating pies (both sweet and savory) as a play on the word “pi.” Schools and educational institutions organize math-related activities, competitions, and pi memorization contests. The San Francisco Exploratorium continues to host annual celebrations featuring pi-themed activities and rituals, including a parade where participants march to the tune of pi digits.

Some math enthusiasts celebrate at exactly 1:59 PM, making the time 3/14 1:59, which represents the first six digits of pi (3.14159). In 2015, celebrations were particularly special as the date (3/14/15) represented the first five digits of pi.

Fun Facts About Pi

Pi has been calculated to over 50 trillion digits beyond its decimal point. As an irrational and transcendental number, it continues infinitely without repetition or pattern.

The ancient mathematician Archimedes of Syracuse was the first to calculate the value of pi using the Pythagorean theorem.

Some math lovers also celebrate Pi Approximation Day on July 22, as the fraction 22/7 is a common approximation of pi.

Albert Einstein was born on Pi Day (March 14, 1879), adding another reason to celebrate this mathematical holiday.

Quiz

When is Pi Day celebrated?
Who founded Pi Day?
In what year was Pi Day officially recognized by the U.S. government?
What is pi used for in the real world?
What food is traditionally eaten on Pi Day?

(Answers: 1. March 14, 2. Larry Shaw, 3. 2009, 4. Engineering, physics, construction, and many scientific fields, 5. Pie)

FAQs

What is National Pi Day?
National Pi Day celebrates the mathematical constant π (pi) on March 14th.

How did National Pi Day originate?
Larry Shaw initiated the first celebration in 1988 at the Exploratorium.

What is the significance of pi in mathematics?
Pi is a fundamental mathematical constant that defines the ratio of a circle’s circumference to its diameter. It’s essential for calculations in numerous fields including engineering, physics, and construction.

Are there alternative dates for celebrating pi?
Yes, some people celebrate Pi Approximation Day on July 22 (22/7 in day/month format). Others observe Tau Day (Two-Pi Day) on June 28, celebrating tau (τ), which equals 2π or approximately 6.28.

How do schools celebrate Pi Day?
Schools often organize math competitions, pi memorization contests, educational activities about the history and applications of pi, and of course, serve pie to students and staff.

Can anyone participate in National Pi Day celebrations?
Yes, people around the world celebrate through various fun and educational activities.

Importance of Pi Day

Pi Day serves as an opportunity to promote interest in mathematics and science education. By making math fun and accessible through celebrations, competitions, and pie-eating, Pi Day helps engage students and the general public with mathematical concepts.

The holiday also honors the importance of pi in our everyday lives. From engineering and construction to physics and astronomy, pi is a crucial component of countless formulas and calculations that shape our understanding of the world.