# What Is Pi Day? Definition and Ways to Celebrate 2 Recently updated !

### Question: What Is Pi Day? When Is It?

Know this symbol before Pi Day! This is Greek letter pi, which is used to denote the number pi.

Answer: March 14 (03/14) is Pi Day, in honor of the number that is referred to as pi. Pi is the ratio of a circle’s circumference to its diameter, which comes out to be 3.14159… (The calculation has been carried out past a trillion digits so far). Pi is an important mathematical constant, so a day was designated to honor it.

How to Celebrate Pi Day

There are lots of ways to honor the number pi:

• Eat pie or pizza. Watch for great Pi Day deals!
• Make Pi Day cookies. Yes, there are even cookie cutter shaped like pi.
• Watch movies with a math theme or the word “pi” in the title. Try “Life of Pi” or “Pi”.
• Wear a Pi Day t-shirt. Some great Pi Day-themed shirts are also funny, like chicken pot pi (with a chicken in a flower pot and the letter pi), Pi-rates (a swashbuckling pi, complete with eyepatch and cutlass), and Octo-pi (octopus + pi).
• Run a Pi Day marathon. You can go 3.14 kilometers or miles.
• Memorize as many digits of pi as you can.
• Since Pi is an irrational number, you could simply be irrational all day.

Learn More About Pi Day