What Is Pi Day 2024. Pi day is celebrated on march 14th (3/14) around the world. If you couldn't already tell by the number this mathematical symbol represents, pi day is on thursday, march 14, 2024.

Pi (greek letter “ π ”) is the symbol used in mathematics to represent a constant — the ratio of the circumference of a circle to its diameter — which is approximately 3.14159. That’s because the date is written as 3/14 (at least in.