Pi (π) Day - March 14, 2021

Pi (π) Day “Round” Table + Listening Party
1:15–2:00 p.m.
Free online event—join via Facebook or YouTube

No matter how you slice it, you won’t want to miss Pi (π) Day—we’ll be celebrating differently this year, but you can still join the party for this irrational and transcendent figure. Math artist John Sims will host a live listening session featuring work from his music project 31415: The Pi Collection. This performance will present his work: "Pi Day Anthem" video, a spoken-word "Dear Pi" letter, and the world premiere of a new "Jazz Pi" composition. Then join our panel of pi enthusiasts dishing out bites of pi trivia and pi art (along with a side of puns and pi-kus), and ask your questions and share your pi stories in the live chat.

Check out our pi activities to snack on at home, four new pi-themed videos in the player on this page, new servings of pi curiosities, and share your own celebrations below.

What is Pi (π) Day?

Founded in 1988 at the Exploratorium, Pi (π) Day has become an international holiday, celebrated live and online all around the world. The numbers in the date (3/14) match the first three digits of the mathematical constant pi (π).

What is π, anyway? Divide any circle’s circumference by its diameter; the answer (whether for a pie plate or a planet) is always approximately 3.14, a number we represent with the Greek letter π. Keep calculating π’s digits with more and more accuracy—as mathematicians have been doing for 4,000 years—and you’ll discover they go on literally forever, with no pattern.