Why is pie day celebracted on March 14th?

Pi Day is celebrated on March 14th because 3, 1, and 4 are the first three digits of pi (π), or the ratio of a circle's circumference to its diameter. In many countries such as the United States, these numbers are written as the month/day, i.e., 3/14, hence March 14th is commonly observed as Pi Day worldwide. This date gained particular recognition as Pi Day, especially in scientific and mathematical communities, for its close approximation to the actual value of pi.