Pi Day Facts for Kids

Quick facts for kids Pi Day
Larry Shaw, the organizer of the first Pi Day celebration, at the Exploratorium in San Francisco
Observed by	United States
Type	Mathematical
Significance	3, 1, and 4 are the three most significant figures of $π$ in its decimal representation.
Celebrations	Pie eating, pi memorization competitions, discussions about $π$
Date	March 14
Next time	March 14, 2026 (2026-03-14)
Frequency	Annual
First time	1988
Related to	Pi Approximation Day

Pi Day is a yearly celebration for the famous mathematical constant called pi ( $π$ ). Pi is a special number that starts with 3.14 and goes on forever without repeating. That's why Pi Day is celebrated on March 14 (written as 3/14 in the United States).

The first Pi Day was held in 1988 by a physicist named Larry Shaw at the Exploratorium, a science museum in San Francisco. People celebrate by eating pie, holding contests to see who can recite the most digits of pi, and talking about this amazing number.

In 2009, the U.S. government officially recognized Pi Day. Later, in 2019, UNESCO made it the International Day of Mathematics, so now people all over the world can celebrate math on March 14!

History of Pi Day
- Super Pi Day
How People Celebrate
- Pi Day at Universities
Other Dates for Pi Fans
Gallery
See also

History of Pi Day

The first big Pi Day party was organized by Larry Shaw in 1988 at the San Francisco Exploratorium. He and other people marched in a circle and then ate fruit pies. The Exploratorium still celebrates Pi Day every year.

On March 12, 2009, the U.S. House of Representatives passed a special resolution to officially name March 14 as National Pi Day. This helped make the holiday even more popular.

Even big companies like Google have joined the fun. For Pi Day in 2010, Google made a special logo, called a Google Doodle, with circles and pi symbols. For the 30th anniversary in 2018, the doodle was a pie recipe from the famous baker Dominique Ansel.

Super Pi Day

The year 2015 was extra special. On March 14, 2015, the date was written as 3/14/15. These are the first five digits of pi (3.1415)! This day was called "Super Pi Day."

At exactly 9:26:53, the date and time together (3/14/15 at 9:26:53) matched the first ten digits of pi. For a single moment, it was like all the digits of pi were perfectly aligned with the clock and calendar.

How People Celebrate

A sign at a food market in Colts Neck, New Jersey, offering a special price on pies for Pi Day.

Pi Day is celebrated in many fun ways. The most popular traditions are eating pie and having contests. This is because the words "pi" and "pie" sound the same in English. Plus, many pies are round, just like the circles that pi helps us measure.

Many pizza places and bakeries offer special deals on Pi Day, like selling pies for $3.14. Schools often hold competitions to see which student can remember and recite the most digits of pi from memory.

Pi Day at Universities

The Massachusetts Institute of Technology (MIT), a famous university for science and technology, often sends its acceptance letters to new students so they arrive on Pi Day. Since 2012, MIT has posted the decisions online at 6:28 p.m. on Pi Day. They call this "Tau Time" because the number tau (τ) is equal to 2 times pi, or about 6.28.

In Princeton, New Jersey, the town celebrates both Pi Day and Albert Einstein's birthday, which is also on March 14. Einstein lived in Princeton for over 20 years. The town holds pie-eating contests and even an Albert Einstein look-alike contest.

Other Dates for Pi Fans

While March 14 is the most famous day, there are other dates when people celebrate pi and related numbers.

Pi Approximation Day is on July 22. This date is written as 22/7 in the day/month format. The fraction 22⁄7 is a close estimate of pi. It was first figured out by the ancient Greek mathematician Archimedes.

Tau Day is on June 28 (6/28). The number tau (τ) is another important math constant that is equal to 2 $π$ , or about 6.28. Some people think tau is an easier number to use in math formulas. People who celebrate Tau Day sometimes joke that you should eat "twice the pie."

Some people also celebrate pi on November 10, because it is the 314th day of the year.