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National Pi Day

A fun observance on March 14 celebrating the mathematical constant pi (approximately 3.14159), observed with pie-eating, marches, and math activities.

Sunday

March 2027

Last updated February 26, 2026 · by the Holiday Calendar Team

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YEARLY DATEMarch 14

OBSERVED INUnited States

CATEGORYSchool

SUBCATEGORYSTEM

ORIGIN

Individual Initiative

FOUNDING ENTITY

Larry Shaw

FIRST OBSERVED

1988

HOW THE HOLIDAY CAME TO BE

Physicist Larry Shaw founded Pi Day in 1988 at the San Francisco Exploratorium, organizing the first celebration on March 14 (3/14) at 1:59 p.m. to honor the mathematical constant pi through a circular march and pie-eating, aiming to make math fun and accessible. In 2009, the U.S. House of Representatives passed non-binding resolution H.Res.224 supporting its designation as National Pi Day.

News Archivevia en.wikipedia.org

INTRO

Introduction

PHOTO

Get ready to celebrate National Pi Day on March 14th! This day honors the mathematical constant pi (π), which is used in calculations involving circles and other shapes. The number, which is 3.14159, was first discovered by ancient Babylonians around 2000BCE and has been studied ever since by mathematicians all over the world. On this special day, take some time to appreciate the beauty of mathematics and enjoy a delicious slice of pie!

DEALS & OFFERS

2026’s deals have wrapped

See who celebrated this year, and browse offers from past years.

Offers wrapped for 2026

National Pi Day ran on March 14. Here’s who celebrated with offers this year.

14 brands offered a deal this year

7-Eleven

Newk’s Eatery

Blaze Pizza

Grand Traverse Pie Company

Crust Pizza Co.

Marco’s Pizza

BJ’s Restaurant & Brewhouse

Matchbox Restaurants +6 more

See past offers

TIMELINE

National Pi Day Timeline

Early Calculation of Pi

Archimedes of Syracuse, an ancient Greek mathematician and engineer, was one of the first to calculate an accurate estimation of pi.

Introduction of Pi Symbol

The Greek letter "π" was first used to represent the mathematical constant by Welsh mathematician William Jones.

Pi Bill Failure

The "Indiana Pi Bill", which inadvertently suggested a value of pi to be 3.2, was introduced in Indiana. It failed to become law due to mathematicians' intervention.

Inception of Pi Day

Physicist Larry Shaw organized the first Pi Day celebration at the San Francisco Exploratorium.

Pi Day Recognition

Congress passes resolution 111, officially recognizing March 14 as National Pi Day in the United States of America.

Ongoing Celebrations

National Pi Day is now celebrated globally by mathematics enthusiasts. It includes activities like pie-eating, pie-throwing, and discussions about the mathematical constant.

GET INVOLVED

How to Celebrate National Pi Day

Bake a pie

Whether you prefer apple, cherry, peach or blueberry, National Pi Day is the perfect excuse to make your favorite pie from scratch. Get creative with your crust and add in some special ingredients to make it even more delicious.

EAT

Eat pi(e)

Take advantage of all the Pie Deals offered on National Pi Day. Many restaurants and bakeries offer discounts on pies and other desserts.

HOST

Host a pi party

Invite friends over for an afternoon or evening of celebrating all things pi. Serve up a variety of pies, play pi related games, watch movies about math or baking, and be sure to include some fun activities that have to do with the mathematical constant.

LEARN

Learn pi

Challenge yourself to memorize as many digits of pi as you can on National Pi Day. You can also learn about where this mathematical constant comes from and how it's used in real life.

ENJOY

Enjoy pie inspired activities

On National Pi Day, get creative! Wear a pie shaped hat, read a book about baking pies, draw a picture of your favorite type of pie or create a paper mache model of pi.

WHY THIS DAY MATTERS

Why National Pi Day is Important

It's a fun event for all ages

Of course, National Pi Day isn't just about serious mathematics - it's also an opportunity for everyone to get involved in festive activities and enjoy some yummy treats! From eating delicious slices of pie to building pi structures out of paper, there's something for everyone on this special day.

It celebrates mathematics and scientific discovery

National Pi Day is a great opportunity to celebrate math and science. Not only does it honor the mathematical constant of pi (3.14), but it also serves as a reminder of the importance of mathematics in our everyday lives, from engineering to architecture to medical sciences.

It recognizes the accomplishments of famous mathematicians

Pi Day is also an excellent way to recognize and pay homage to the work of some of the world's most influential mathematicians and scientists, from ancient Greek philosophers like Pythagoras to more modern thinkers like Albert Einstein. It's a day for us to appreciate their contributions that have shaped our understanding of the world around us.

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