Pi Day,” which is March 14, 3.14, is a day meant to recognize the special, infinite number that can also be recognized by its ...

Pi refers to the ratio of a circle’s circumference to its diameter. The concept was popularised in 1988 when physicist Larry Shaw organised the first Pi Day event at the San Francisco Exploratorium.

Pi Day 2026 is celebrated on March 14 to honour the mathematical constant π (3.14). Learn its history, significance, world records and fun ways people celebrate this global math day.