image of the Greek character Pi

Every March 14 is international Pi Day when math enthusiasts around the world celebrate the famous constant Pi, equal to the ratio of the circumference of a circle to its diameter. Pi Day is celebrated on March 14 because its first 3 digits are 3.14 (representing March 14th using notation). March 14 is also Albert Einstein's birthday (he would be 138 years old in 2017). Pi is an irrational number, meaning that the sequence of its decimal digits continues forever without repeating itself.


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About this site:

The domain name "" is a play on the phrase "pie in the sky" — a fitting metaphor for this special transcendental number and natural embodiment of the infinite. No matter how good we get at computing the decimal digits of Pi, there will forever be one... more... digit...

The background image for this page is a graphic representation of 1,310,720 digits of Pi, where each digit is indicated by a pixel of a different color. It was obtained from here.

This website is a production of, in recognition of contribution of math to the success of humanity.

Happy Pi Day! :-Π