Pi Day 2027
March 14, 2027
About Pi Day 2027
Pi Day 2027 is Sunday 14 March 2027. Pi Day is always March 14, written 3/14 in the US date format to match the first three digits of pi (3.14), and it is recognized by the US House of Representatives and celebrated by the Exploratorium in San Francisco, where it began.
| Year | Date | Status |
|---|---|---|
| 2026 | Saturday 14 March 2026 | Fixed date |
| 2027 | Sunday 14 March 2027 | Fixed date |
| 2028 | Tuesday 14 March 2028 | Fixed date |
What is Pi Day?
Pi Day celebrates the mathematical constant pi, the ratio of a circle’s circumference to its diameter, which begins 3.14159 and continues forever without repeating. The first Pi Day was held in 1988 at the Exploratorium science museum in San Francisco, organized by physicist Larry Shaw, and involved staff and visitors walking around a circular space and eating fruit pies. In 2009 the US House of Representatives passed a resolution supporting the designation of March 14 as National Pi Day.
The day is now marked in schools, universities and tech companies around the world, and March 14 is also Albert Einstein’s birthday, which adds to the appeal for science teachers. In the UK and elsewhere it sits alongside the springtime maths celebrations such as World Maths Day and British Science Week. You can find the history and activity ideas on the Exploratorium’s Pi Day page and at piday.org.
Why it matters
Math anxiety is common and starts young, and Pi Day is one of the few days when math is genuinely fun and visible. Pi turns up in everything from GPS and engineering to the shape of planets and the design of a bicycle wheel, so the day is an easy way to show that math describes the real world. It is also cheap to celebrate: a piece of string, a few round objects and a calculator are enough to let students discover the constant for themselves.
For schools: assembly, classroom and PTA ideas
Pi Day usually belongs to the math department or a math lead teacher, with the PTA stepping in for pie sales. In 2027 it falls on a Sunday, so most schools will celebrate on Friday March 12 or Monday March 15; plan in February.
- Assembly: a pi digit recital challenge on stage, with a prize for the student who remembers the most digits.
- Assembly: a two-minute “where is pi hiding” talk with real objects: a clock, a ball, a wheel and a pizza.
- Classroom: measure circumference and diameter of several circular objects and calculate pi from the results.
- Classroom: a pi skyline art activity where each digit becomes a bar of that height, or a pi bracelet with colored beads.
- Whole school: a pi-themed dress day (circles, Einstein hair or math T-shirts) with a pi trivia quiz at lunch.
- Parents and PTA: a pie sale or pie-baking contest at 3:14pm, with proceeds going to math club or new manipulatives.
Ideas for brands and organisations
- Offer a $3.14 deal or 31.4 percent discount on a relevant product for the day.
- Run a social media digit-recital or “circle in your workplace” photo challenge.
- Sponsor a local school’s Pi Day prizes or a coding and math club.
- Share a short explainer on how your engineers or analysts use pi in their work.
Frequently asked questions
Why is Pi Day on March 14?
Because the US date format writes March 14 as 3/14, matching the first three digits of pi. Pi Approximation Day is July 22, or 22/7, which uses a common fraction for pi.
What is Pi Day 2027’s day of the week?
Pi Day 2027 falls on a Sunday, so schools and workplaces usually celebrate on the nearest weekday.
How many digits of pi are known?
Pi has been computed to well over 100 trillion digits using supercomputers, although only about 40 digits are needed to calculate the circumference of the observable universe to the width of an atom.
Published 28 August 2026: dates checked for 2026 to 2028.
2026 Awareness Days Wall Planner
Every key awareness day at a glance. Perfect for offices, staff rooms, and team planning.
View Calendar →
