Pi Day, celebrated annually on March 14 (3/14), commemorates the mathematical constant π (pi), using its first three digits. Originating in 1988 at San Francisco's Exploratorium, celebrations often include consuming pie and pi recitation contests. The U.S. House of Representatives backed Pi Day in 2009. UNESCO declared March 14 as the International Day of Mathematics in 2019.
1988: First Pi Day Celebration
In 1988, Larry Shaw, an employee at the San Francisco Exploratorium, founded Pi Day.
1988: First Pi Day Celebration
The first known large-scale celebration of Pi Day was organized in 1988 by Larry Shaw at the San Francisco Exploratorium, involving staff and public marching around a circular space and consuming fruit pies.
March 12, 2009: U.S. House of Representatives Resolution for Pi Day
On March 12, 2009, the U.S. House of Representatives passed a non-binding resolution (111 H. Res. 224), recognizing March 14, 2009, as National Pi Day.
March 14, 2009: National Pi Day Recognition
March 14, 2009 was recognized as National Pi Day by the U.S. House of Representatives.
2009: U.S. House of Representatives supports Pi Day
In 2009, the United States House of Representatives passed a non-binding resolution supporting the designation of Pi Day.
2012: MIT Application Decisions on Pi Day
Starting in 2012, MIT began posting application decisions online on Pi Day, initially at 6:28 pm, referred to as "Tau Time".
March 2014: Pi Month Celebration
Some people observed the entire month of March 2014 as "Pi Month."
2015: MIT Application Decisions at Pi Minute
In 2015, MIT released application decisions online at 9:26 am, coinciding with that year's "pi minute."
2015: Super Pi Day
The year 2015 marked a special occasion, dubbed "Super Pi Day", as the date 3/14/15 reflected the first five digits of pi.
November 2019: UNESCO designates Pi Day as International Day of Mathematics
In November 2019, UNESCO's 40th General Conference designated Pi Day as the International Day of Mathematics.
2020: MIT Application Decisions Reflecting Pi Digits
In 2020, MIT released application decisions online at 1:59 pm, representing the first six digits of pi.