Pi Day is the annual math holiday on March 14 (3/14), matching the first three digits of the constant π ≈ 3.14159[1].

Where did Pi Day come from?

Physicist Larry Shaw started it at the San Francisco Exploratorium on March 14, 1988 with a circular march and a fruit-pie snack[1][3].

What does Pi Day mean?

It's a celebration of π and, by extension, math and science more broadly, helped along by the coincidence that Einstein was born on the same day[1].

How do you use Pi Day?

People bake or eat pies, post memes about circles and equations, and post how many digits of π they can recite from memory[4].

Is Pi Day still popular?

Yes, it is still an annual online tradition every March 14, boosted by Google Doodles[5] and a 2009 U.S. congressional resolution that made it 'National Pi Day'[2].

Pi Day

1988eventclassic

Published September 21, 2026

Pi Day is the annual math holiday celebrated on March 14, whose numeric date (3/14) matches the first three digits of π (about 3.14159). What began as a small 1988 procession at the San Francisco Exploratorium grew into an internet tradition of pie puns, memorized-digit bragging contests, and Einstein-themed math jokes each year.

math memes annual tradition memes seasonal memes pun memes pre digital memes

Overview

Pi Day mixes genuine math appreciation with dumb wordplay. The joke rides on the phonetic overlap between π and pie, so posts, classroom events, and memes on March 14 pivot on pie-eating gags, pie-throwing bits, and photos of circular baked goods labeled with strings of digits1. Reciting memorized digits of π grew into its own bragging tradition, with self-identified math geeks posting how far they can go from memory4.

The holiday also folds in Albert Einstein, whose birthday falls on March 14, so celebrations often stretch into a general science theme rather than just π itself1. Google marks the date with themed Pi Day Doodles5, and MIT times its regular admissions decisions to Pi Day, turning the holiday into a running joke among high schoolers waiting on results3. Some math purists also nod to July 22 (22/7), the older fractional approximation, but the 3/14 version is the one that stuck online4.

Origin & Background

Platform

San Francisco Exploratorium (offline origin) / math forums and blogs (online spread)

Creator

Larry Shaw

Date

1988

The first Pi Day happened on March 14, 1988, organized by American physicist Larry Shaw at the San Francisco Exploratorium1. Staff scientists and visitors marched in a circular procession around one of the museum's rotundas and then ate fruit pies afterward, locking in the food pun that still defines the holiday3. Because March 14 also happens to be Einstein's birthday, Shaw's team let the day expand into a broader celebration of math and science, not just π on its own1.

Pi Day

Overview

Origin & Background

How It Spread

Frequently Asked Questions

References (5)