Now available for Slack and Discord Add to Slack Add to Discord
Obscure Holiday Calendar icon
Obscure Holiday Calendar Daily fun, weird, and wonderful observances
Overview Also on this date Celebrate Fun facts FAQ Related
Annual observance

Pi Day

March 14 Food / Dessert Updated 2025-12-17

This holiday is featured in the Obscure Holiday Calendar app with emoji-style visuals, reminders, and daily fun facts.

Download on the App Store Get it on Google Play

Overview

Pi Day is an annual celebration of the mathematical constant π (pi). It is observed on March 14th (3/14 in the month/day format), because 3, 1, and 4 are the first three significant digits of π. The day is often celebrated by math enthusiasts and educators with various activities, including eating pie (a homophone for "pi") and engaging in contests or discussions related to mathematics.

Observed each year on March 14, Pi Day invites people to pause, share the story, and bring a little themed joy to their day.

Why it matters: Pi Day, celebrated on March 14, honors the mathematical constant π while playfully linking it to the enjoyment of pie. This unique holiday not only highlights the significance of mathematics in our lives but also brings together food lovers and math enthusiasts in a delicious celebration of both disciplines.

Origin and story

Pi Day is also the birthday of renowned physicist Albert Einstein.

The first known large-scale celebration of Pi Day was organized by physicist Larry Shaw at the San Francisco Exploratorium in 1988.

Quick facts

  • DateMarch 14
  • TypeFood / Dessert
  • Great forFoodies, Chocolate lovers, Home bakers

Also on this date

Ways to celebrate

  • Enjoy a slice of pie and share a math fact.
  • Learn the basics at NASA’s “What Is Pi?”.
  • Read a deeper overview at Encyclopaedia Britannica.
  • Try a short puzzle, recite digits of pi, or explore circles in real life.
  • Use the day to spark math curiosity with friends or students.

Fun facts

  • Pi Day is also the birthday of renowned physicist Albert Einstein.
  • The first known large-scale celebration of Pi Day was organized by physicist Larry Shaw at the San Francisco Exploratorium in 1988.
  • In 2009, the U.S. House of Representatives passed a non-binding resolution recognizing March 14th as National Pi Day.
  • Pi is an irrational number, which means it has an infinite number of digits that do not repeat in a pattern.
  • March 14th also coincides with International Day of Mathematics, celebrated by UNESCO.

Sources and attribution

Source not provided.

Continue to

FAQ

When is Pi Day?
It is observed on March 14 each year.
What is Pi Day?
Pi Day celebrates the mathematical constant π and its role in geometry and science.
How do people celebrate Pi Day?
People enjoy pie, solve puzzles, and explore math concepts.

Get the app

Thousands of obscure holidays, daily widgets, reminders, and fun facts—free on iOS and Android.

Download on the App Store Get it on Google Play

Recently viewed holidays