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NATIONAL PI DAY

When is National Pi Day in 2025?

National Pi Day in 2025 is on the Friday, 14th of Mar (3/14/2025).

National Pi Day is on the 73th day of 2025. There are 292 days left in the year.

National Pi Day Facts

  • Date: Mar 14, 2025
  • Fun
  • Also Called: Pi Day
  • Celebrations: Eating, Partying, Contests
National Pi Day iImage Credit: PixaBay.com

Pi (π) is a mathematical symbol representing the ratio of the circumference of a circle to its diameter. The ratio is approximated as 3.14, but it’s calculated to over one trillion digits beyond the decimal point. Pi (π) is a vital key in Mathematical geometry and equations. The surface area and perimeter of circular objects depend on the symbol for accurate results. Observed on March 14th, National Pi Day is an opportunity for Math enthusiasts to showcase their love for numbers. National Pi Day should however not be confused with Pi Approximation Day observed ion June 22nd or Two Pi Day marked on June 28th.

Who Invented Pi?

According to historians, the first person to calculate pi was Archimedes of Syracuse. He was one of the ancient Greek mathematicians of the world, and he lived in the 3rd century. Archimedes used the Pythagorean Theorem alongside two regular polygons to calculate the area of a circle. Archimedes approach was theoretical, and it showed that pi was between 3 1/7 and 3 1/10. The use of Pi was popularized in the 1700s by William Jones and Leonhard Euler.

History of National Pi Day

Pi (π) has a rich history. Various ancient civilizations have been linked to the calculation of the Pi (π). Among them are Egyptians and Babylonians. Babylonians determined the area of a circle by squaring the radius and then multiplying it by three. This gave a value of 3 which is a close approximation to pi. For the Egyptians, they would calculate the area of a circle by a formula that approximated pi as 3.1605.

Pi is also biblical. In the Old Testament, (1 Kings 7:23), a circular pool is said to be 30 cubits around and ten cubits wide. This again gives the value of pi as 3 or thereof.

The first records of National Pi Day are traced in 1988 in San Francisco. The day was meant to draw attention to the STEM fields (science, technology, engineering, and math.) The celebrations were organized by physicist Larry Shaw, who led the public in marching around circular spaces and consuming fruit pies.

On March 12, 2009, a non-binding resolution was passed by the US Congress where March 14th was officially recognized as the National Pi Day. The entire month of March is also observed as the National Pi month. The date was chosen since it coincides with the first three significant digits of pi which are 3, 1 and 4. Interestingly, Albert Einstein’s birthday also falls on March 14th.

How to Celebrate National Pi Day

You can observe National Pi Day by eating pies and other circular treats. Pi and pie are English homophones, and the coincidental circular form of pie makes it the best treat of the day.

If you love Mathematics, mark the day by holding a pi memorization contest with friends. Although pi can be calculated to infinite numbers, figure out who among your friends can recite most of the numbers as they follow each other. Google has a training app for the same to help you in the contest.

Another great way to mark this day is by celebrating Albert Einstein’s birthday. You can attend celebrations in Princeton, New Jersey where a major event to mark the pi day and Einstein’s birthday is held. Some of the Pi Day activities you can take part in during the event include dressing like the Nobel Prize winner. If declared the winner of the Einstein’s Look-Alike contest then you will be lucky to go home with a great award. The German-born theoretical physicist lived in Princeton for 20 years while working at one of the institutes there.

You can also dazzle your friends by posting a pi-themed trivia on social media. Remember to share with them the practical problems in real life that pi help us solve. Spread all this enthusiasm using the hashtag #NationalPiDay.

Interesting National Pi Day Fun Facts

- Pi (π) is the 16th digit of the Greek alphabet.

- In the 18th century, Pi (π) was proved to be an irrational number. This means that it is decimal representation is infinite and never repeats.

- Lu Chao from China holds the World Record for memorizing the first 67,890 digits of the Pi (π).

- Only the first 39 digits of Pi (π) are required to give an accurate answer of any Pi (π) mathematical problems.

National Pi Day Observances

DAY
DATE
HOLIDAY NAME
  • Mon
  • Mar 14, 2022
  • Tue
  • Mar 14, 2023
  • Thu
  • Mar 14, 2024
  • Fri
  • Mar 14, 2025

List of National and Regional Public Holidays of United States in 2025

DAYDATEHOLIDAY
WednesdayWedJan 01, 2025Jan 01New Year's Day
MondayMonJan 20, 2025Jan 20M L King Day
MondayMonFeb 17, 2025Feb 17Presidents' Day
FridayFriApr 18, 2025Apr 18Good Friday
SundaySunApr 20, 2025Apr 20Easter Sunday
MondayMonMay 26, 2025May 26Memorial Day
ThursdayThuJun 19, 2025Jun 19Juneteenth
FridayFriJul 04, 2025Jul 04Independence Day
MondayMonSep 01, 2025Sep 01Labor Day
MondayMonOct 13, 2025Oct 13Columbus Day
TuesdayTueNov 11, 2025Nov 11Veterans Day
ThursdayThuNov 27, 2025Nov 27Thanksgiving Day
ThursdayThuDec 25, 2025Dec 25Christmas

List of Popular Celebration Days of United States in 2025

DAYDATEHOLIDAY
SundaySunJan 12, 2025Jan 12National Pharmacists Day
SundaySunJan 19, 2025Jan 19National Popcorn Day
SundaySunFeb 02, 2025Feb 02Groundhog Day
WednesdayWedFeb 05, 2025Feb 05National Signing Day
FridayFriFeb 07, 2025Feb 07National Wear Red Day
SundaySunFeb 09, 2025Feb 09National Pizza Day
ThursdayThuFeb 13, 2025Feb 13Galentine's Day
FridayFriFeb 14, 2025Feb 14Valentine's Day
SaturdaySatFeb 15, 2025Feb 15National Bagel Day
TuesdayTueFeb 18, 2025Feb 18National Drink Wine Day
SaturdaySatFeb 22, 2025Feb 22National Margarita Day
TuesdayTueMar 04, 2025Mar 04National Pancake Day
FridayFriMar 07, 2025Mar 07National Cereal Day
FridayFriMar 07, 2025Mar 07National Employee Appreciation Day
SundaySunMar 09, 2025Mar 09Daylight savings
MondayMonMar 10, 2025Mar 10National Napping Day
FridayFriMar 14, 2025Mar 14National Walkout Day
FridayFriMar 14, 2025Mar 14National Pi Day
ThursdayThuMar 20, 2025Mar 20National Proposal Day
SundaySunMar 23, 2025Mar 23National Puppy Day
SundaySunMar 30, 2025Mar 30National Doctor Day
WednesdayWedApr 02, 2025Apr 02National Walking Day
ThursdayThuApr 03, 2025Apr 03National Burrito Day
MondayMonApr 07, 2025Apr 07National Beer Day
FridayFriApr 11, 2025Apr 11National Pet Day
SaturdaySatApr 12, 2025Apr 12National Grilled Cheese Day
ThursdayThuMay 01, 2025May 01National Day Of Prayer
SundaySunMay 11, 2025May 11Mother's Day
SundaySunMay 25, 2025May 25National Towel Day
SundaySunMay 25, 2025May 25National Wine Day
FridayFriJun 06, 2025Jun 06National Donut Day
SundaySunJun 08, 2025Jun 08National Best Friends Day
SundaySunJun 15, 2025Jun 15Father's Day
SaturdaySatJun 21, 2025Jun 21National Selfie Day
SundaySunJun 22, 2025Jun 22National Kissing Day
SundaySunJul 13, 2025Jul 13National French Fry Day
MondayMonJul 14, 2025Jul 14National Nude Day
WednesdayWedJul 16, 2025Jul 16National Hot Dog Day
SundaySunJul 20, 2025Jul 20National Ice Cream Day
WednesdayWedJul 23, 2025Jul 23Amazon Prime Day
ThursdayThuJul 24, 2025Jul 24National Tequila Day
TuesdayTueJul 29, 2025Jul 29National Chicken Wing Day
FridayFriAug 01, 2025Aug 01National Girlfriends Day
SundaySunAug 03, 2025Aug 03National Sister Day
ThursdayThuSep 18, 2025Sep 18National Cheeseburger Day
FridayFriOct 03, 2025Oct 03National Boyfriends Day
SaturdaySatOct 04, 2025Oct 04National Vodka Day
SaturdaySatOct 04, 2025Oct 04National Taco Day
ThursdayThuOct 09, 2025Oct 09Leif Erikson Day
SaturdaySatOct 18, 2025Oct 18Sweetest Day
WednesdayWedOct 29, 2025Oct 29National Cat Day
FridayFriOct 31, 2025Oct 31Halloween
MondayMonNov 03, 2025Nov 03National Sandwich Day
FridayFriNov 28, 2025Nov 28Black Friday
MondayMonDec 01, 2025Dec 01Cyber Monday
SaturdaySatDec 06, 2025Dec 06Candle Day
TuesdayTueDec 09, 2025Dec 09National Pastry Day
FridayFriDec 19, 2025Dec 19National Ugly Sweater day