When is Pi Day?

Upcoming dates

• 2027Sun, March 14
• 2028Tue, March 14
• 2029Wed, March 14
• 2030Thu, March 14

When is Pi Day?

Pi Day always falls on March 14, a fixed calendar date, so the weekday changes from year to year. Written as 3/14 in the month-day format used in the United States, the date matches the first three digits of pi.

It is not a public holiday, so offices, schools, and businesses stay open. It is a celebration of mathematics and science rather than an official day off, and it is especially popular in classrooms.

What Pi Day celebrates

Pi is the ratio of a circle's circumference to its diameter, an irrational number whose digits continue endlessly without repeating. It begins 3.14159 and appears throughout mathematics, science, and engineering.

The observance is widely credited to physicist Larry Shaw, who organized an early celebration at the San Francisco Exploratorium in 1988. In 2009 the United States House of Representatives passed a resolution recognizing March 14 as Pi Day.

How Pi Day is celebrated

Schools and math enthusiasts mark the day with activities such as reciting the digits of pi, solving puzzles, and exploring the geometry of circles. Some people hold contests to see who can remember the most digits.

Because 'pi' sounds like 'pie,' eating and baking pies is a popular tradition, and the round shape ties neatly to the mathematics. The date also happens to be the birthday of Albert Einstein, which adds to the appeal for science fans.

Frequently asked questions

When is Pi Day?

Pi Day is on March 14, 2027.

What day of the week is Pi Day?

This year, Pi Day falls on a Sunday.

How many days until Pi Day?

190 days.