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Pi (π) Day

  • About Pi (π) Day
  • Guide to Celebrating Pi (π) Day
  • A Brief History of Pi (π)
  • A Slice of Pi (π) Day History
  • Pi (π) Day Activities
 

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Pi (π) Day - March 14, 2021

Celebrate Pi (π) Day online with the Exploratorium.

 

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.

Pi (π) Day “Round” Table + Listening Party
Why Pi?
Pi: the Story of an Extra Little Bi
Pi is Women's Work: Celebrating Women in Mathematics
When Pi isn't Enough
Pi Day 2020: Why π?
Pi Day Celebration
Say it with Trike: Pi Day



Learn More

Guide to Celebrating Pi (π) Day

Celebrate Pi (π) Day wherever you are.

A Brief History of Pi (π)

Learn about the long and rich history of π.

A Slice of Pi (π) Day History

Plumb the history of Pi Day—and its founder, Larry Shaw (pictured). 

Activities

Science activity to demonstrate pi using circumference and string
Cutting Pi

String and scissors are all you need to find pi all around you.

Science activity to estimate pi with the random tossing of toothpicks
Pi Toss

Randomly toss some toothpicks, with pi as your reward.

Science activity using straight lines to learn about circles
Pi Graph

Use straight lines to learn about circles.

At-Home Pi Day Celebrations

Share your celebrations by tagging @Exploratorium #PiDaySF



Exhibits

Pi Has Your Number
Pi Has Your Number

Use a touchscreen to search for any number hidden in the first 3 million digits of pi.

Pi Toss
Pi Toss

Toss some chips to estimate pi.

Pi Shrine
Pi Shrine

This circular piece of Exploratorium history has held pride of place in π Day festivities since 1988.

Pi (π) Day

  • About Pi (π) Day
  • Guide to Celebrating Pi (π) Day
  • A Brief History of Pi (π)
  • A Slice of Pi (π) Day History
  • Pi (π) Day Activities

Donate Today! →

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