• Get Started


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

  • Mon
  • Mar 14, 2022
  • Tue
  • Mar 14, 2023
  • Thu
  • Mar 14, 2024

List of National and Regional Public Holidays of United States in 2024

MondayMonJan 01, 2024Jan 01New Year's Day
MondayMonJan 15, 2024Jan 15M L King Day
MondayMonFeb 19, 2024Feb 19Presidents' Day
FridayFriMar 29, 2024Mar 29Good Friday
SundaySunMar 31, 2024Mar 31Easter Sunday
MondayMonMay 27, 2024May 27Memorial Day
WednesdayWedJun 19, 2024Jun 19Juneteenth
ThursdayThuJul 04, 2024Jul 04Independence Day
MondayMonSep 02, 2024Sep 02Labor Day
MondayMonOct 14, 2024Oct 14Columbus Day
MondayMonNov 11, 2024Nov 11Veterans Day
ThursdayThuNov 28, 2024Nov 28Thanksgiving Day
WednesdayWedDec 25, 2024Dec 25Christmas

List of Popular Celebration Days of United States in 2024

FridayFriJan 12, 2024Jan 12National Pharmacists Day
FridayFriJan 19, 2024Jan 19National Popcorn Day
FridayFriFeb 02, 2024Feb 02Groundhog Day
FridayFriFeb 02, 2024Feb 02National Wear Red Day
WednesdayWedFeb 07, 2024Feb 07National Signing Day
FridayFriFeb 09, 2024Feb 09National Pizza Day
TuesdayTueFeb 13, 2024Feb 13Galentine's Day
TuesdayTueFeb 13, 2024Feb 13National Pancake Day
WednesdayWedFeb 14, 2024Feb 14Valentine's Day
ThursdayThuFeb 15, 2024Feb 15National Bagel Day
SundaySunFeb 18, 2024Feb 18National Drink Wine Day
ThursdayThuFeb 22, 2024Feb 22National Margarita Day
ThursdayThuFeb 29, 2024Feb 29Leap Day
FridayFriMar 01, 2024Mar 01National Employee Appreciation Day
ThursdayThuMar 07, 2024Mar 07National Cereal Day
SundaySunMar 10, 2024Mar 10Daylight savings
MondayMonMar 11, 2024Mar 11National Napping Day
ThursdayThuMar 14, 2024Mar 14National Walkout Day
ThursdayThuMar 14, 2024Mar 14National Pi Day
WednesdayWedMar 20, 2024Mar 20National Proposal Day
SaturdaySatMar 23, 2024Mar 23National Puppy Day
SaturdaySatMar 30, 2024Mar 30National Doctor Day
WednesdayWedApr 03, 2024Apr 03National Walking Day
ThursdayThuApr 04, 2024Apr 04National Burrito Day
SundaySunApr 07, 2024Apr 07National Beer Day
ThursdayThuApr 11, 2024Apr 11National Pet Day
FridayFriApr 12, 2024Apr 12National Grilled Cheese Day
ThursdayThuMay 02, 2024May 02National Day Of Prayer
SundaySunMay 12, 2024May 12Mother's Day
SaturdaySatMay 25, 2024May 25National Towel Day
SaturdaySatMay 25, 2024May 25National Wine Day
FridayFriJun 07, 2024Jun 07National Donut Day
SaturdaySatJun 08, 2024Jun 08National Best Friends Day
SundaySunJun 16, 2024Jun 16Father's Day
FridayFriJun 21, 2024Jun 21National Selfie Day
SaturdaySatJun 22, 2024Jun 22National Kissing Day
SaturdaySatJul 13, 2024Jul 13National French Fry Day
SundaySunJul 14, 2024Jul 14National Nude Day
WednesdayWedJul 17, 2024Jul 17National Hot Dog Day
SundaySunJul 21, 2024Jul 21National Ice Cream Day
TuesdayTueJul 23, 2024Jul 23Amazon Prime Day
WednesdayWedJul 24, 2024Jul 24National Tequila Day
MondayMonJul 29, 2024Jul 29National Chicken Wing Day
ThursdayThuAug 01, 2024Aug 01National Girlfriends Day
SundaySunAug 04, 2024Aug 04National Sister Day
WednesdayWedSep 18, 2024Sep 18National Cheeseburger Day
ThursdayThuOct 03, 2024Oct 03National Boyfriends Day
FridayFriOct 04, 2024Oct 04National Vodka Day
FridayFriOct 04, 2024Oct 04National Taco Day
WednesdayWedOct 09, 2024Oct 09Leif Erikson Day
SaturdaySatOct 19, 2024Oct 19Sweetest Day
TuesdayTueOct 29, 2024Oct 29National Cat Day
ThursdayThuOct 31, 2024Oct 31Halloween
SundaySunNov 03, 2024Nov 03National Sandwich Day
FridayFriNov 29, 2024Nov 29Black Friday
MondayMonDec 02, 2024Dec 02Cyber Monday
SaturdaySatDec 07, 2024Dec 07Candle Day
MondayMonDec 09, 2024Dec 09National Pastry Day
FridayFriDec 20, 2024Dec 20National Ugly Sweater day