The world celebrates Pi Approximation Day every year on 22 July. The fraction 22/7 is an approximate value of Pi, and it is for this reason that this day is commemorated on July 22. In this case, the numerator 22 represents the date, while the numerator seven represents the month.The number, ‘Pi,’ is defined as the circumference to diameter ratio of a circle and is approximately equal to 3.14159. If you plug the numbers into your calculator, you’ll notice that 22 divided by 7 provides an infinite variety of answers. The digits continue indefinitely. That is why Pi is regarded as an approximation, and therefore the rationale for today.
History of Casual Pi Day
For roughly 4,000 years, pi has been known in some form or another. The ancient Babylonians used it to calculate the diameters of circles — about 3.125. Archimedes of Syracuse — one of the finest ancient mathematicians — computed pi for the first time about 250 B.C. He discovered that pi was between 3 1/7 and 3 10/71.Later, in the mid400s, another talented mathematician — Zu Chongzhi — used laborious computations to compute pi once more. Chongzhi invented his technique of calculating pi because Archimedes’ works were stolen and not available in China at the time. Chongzhi and Archimedes were the first scientists to discover pi in its true sense.Later, mathematicians sought to improve the accuracy of pi by employing circumscribed and inscribed polygons. This is how Archimedes computed pi for the first time, and it remained the dominant algorithm for pi computation for the next 1,000 years. In 1630, Austrian astronomer, Christoph Grienberger, obtained the most accurate calculation of pi using this approach — arriving at 38 exact digits.According to legend, Pi Approximation Day and Pi Day are inextricably linked, and Pi Day is celebrated on March 14 every year across the world. Because the value of Pi is 3.14, Physicist Larry Shaw established Pi Day in 1988 at the “Exploratorium.” According to the “San Francisco Science Museum,” the date for Pi Day has been set for 14 March, which is the number of the Pi (3.14). In 2009, the “United States House of Representatives” also backed Pi Day. The Pi Approximation Day, on the other hand, is observed every year on July 22.
Casual Pi Day timeline
Archimedes — a Greek mathematician — is credited with being the first person to successfully calculate pi after developing an algorithm around 250 B.C., which is why pi is also referred to as Archimedes' constant.
Computers compute pi to 31,415,926,535,897 decimal places, as well as its twoquadrillionth digit when represented in binary (0).
Lu Chao of China earns the “Guinness World Record” for reciting 67,890 digits of pi.
Haruka Iwao determines the world's most precise figure of pi which includes 31.4 trillion digits — breaking the previous record of 22 trillion.
Casual Pi Day FAQs
What symbol did pi used for?
Simply said, pi — which is represented as the Greek letter for p, or — is the ratio of a circle’s circumference to its diameter. Pi has a decimal value of about 3.14.
Who was born on Pi Day?
Albert Einstein’s birthday is on March 14 — 3/14 — which is celebrated as Pi Day.
Which famous scientist died on Pi Day?
On March 14, 2018, famed theoretical physicist and cosmologist Stephen Hawking died at his home in Cambridge, England, at the age of 76. Hawking was a celebrity both in the science community and in the public eye.
Casual Pi Day Activities

Have lots of pie
Remember that a pie is actually a circle, so you're not only learning mathematics but also having fun while eating it! Go on, dig in!

Participate in a contest
It has also been noted that many schools and education classes run contests to see whose student recalls Pi to the greatest number of decimal places. The person who knows the most digits in the number wins a pie.

Do some fun challenge
Schoolchildren and mathematicians alike like the challenge of memorizing as many digits of the number as possible! Today, challenge a friend or family member to outperform your knowledge of pi.
5 Interesting Facts About Pi

There is no zero
Pi's first 31 digits include no zeros.

6.4 billion known digits
Pi contains 6.4 billion known digits and it would take a human around 133 years to recite them all without pausing.

First letter of Greek word
Pi(π) is the initial letter of the Greek words ‘periphery’ and ‘perimeter.’

Sixteenth letter
Pi is the 16th letter in both the English and Greek alphabets.

Describe periodic phenomena
Pi is also employed in various physics and engineering formulas to explain periodic phenomena such as pendulum motion, string vibrations, and alternating electric currents.
Why We Love Casual Pi Day

Essential for fundamental calculation
It is required for the simple calculation of the circumference of a circle, but NASA also uses pi in several applications, such as calculating spaceship trajectories! Pi is a necessary constant in some of the most significant arithmetic.

Connect mathematics with the real world
Because pi is associated with circles, it is also associated with cycles, which include ebb and flow, ocean tides, electromagnetic waves, and many other things. Furthermore, many natural world events, such as the form of rivers, the disc of the sun, the helix of D.N.A., and even the pupil of an eye, may be estimated using pi.

We get to eat pie
Apart from how we may use this day as a fun challenge to remember pi, we must first consume a lot of pie before the challenges begin! Who cares about the scale?
Casual Pi Day dates
Year  Date  Day 

2023  July 22  Saturday 
2024  July 22  Monday 
2025  July 22  Tuesday 
2026  July 22  Wednesday 
2027  July 22  Thursday 