Pi Day March 14, 2022: Events, Activities, & History | Exploratorium

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Pi (π) Day Pi (π) Day

Friday, March 14, 2025 • 11:00 a.m.–3:00 p.m.

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Join the 38th annual celebration of our own homegrown holiday! March 14th (3/14) commemorates the irrational, transcendent, and never-ending ratio that helps describe circles of all sizes. Explore math-inspired activities and presentations, then join our pi parade and eat a free piece of pie. Come for the STEAM and stay for the slice!

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 Procession

1:59 p.m.Moore Gallery 4Grab your digit and get in line for the annual Pi Procession! A high-spirited crowd parades through the museum and circles the Pi Shrine 3.14 times, waving the digits of pi and dancing along to a brass band. All participants will enjoy a free slice of pie following the parade.

More details to be announced.

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.

What is pi, 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 pi’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 Celebration with John Sims | Exploratorium Why Pi? Pi: the Story of an Extra Little Bit Pi is Women's Work: Celebrating Women in Mathematics When Pi isn't Enough Pi Day LIVE @ Exploratorium Pi Day Celebration Say it with Trike: Pi Day Pi (π) Day Listening Party Featuring John Sims + “Round” Table Guide to Celebrating Pi (π) Day Celebrate Pi (π) Day wherever you are. A Slice of Pi (π) Day History Plumb the history of Pi Day—and its founder, Larry Shaw (pictured).

Activities

Cutting Pi String and scissors are all you need to find pi all around you. Pi Toss Randomly toss some toothpicks, with pi as your reward. 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 Use a touchscreen to search for any number hidden in the first 3 million digits of pi. Pi Toss Toss some chips to estimate pi. Pi Shrine This circular piece of Exploratorium history has held pride of place in π Day festivities since 1988.