When Is Pi Day?
Pi Day is observed on March 14 in the United States.
What Is Pi Day?
Get ready for a flashback to middle school math class.
First and foremost, Pi Day is a celebration of the mathematical constant, π (pi), or 3.14159265359. As you can see, the date is literally the first three major numbers, when you write March 14 in a numerical format, like 3/14. That's right: Pi Day is about math, but thankfully, someone made it fun with pies. Best of all, a lot of people tend to celebrate the occasion with pizza, too, which arguably makes Pi Day better than National Pie Day.