A little reason to celebrate
Pi Day
Fun · Food · March 14
Pi Day honors the number pi, the ratio behind every circle, with math puzzles, digit recitations and plenty of round pies.
Pi Day falls on Sunday, March 14, 2027. That is 138 days away.
Two things share a name and a shape here. One is the mathematical constant pi, written with a Greek letter. The other is pie, the baked dish with a crust and a filling. Pi Day takes both seriously, which mostly means doing a little math and then eating something round.
The number shows up wherever circles do. It connects a circle's width to the distance around it, and it sits inside the formula for a circle's area, pi times the radius squared. Its decimal digits go on forever without repeating, so nobody ever finishes writing it down. People try anyway. Some memorize dozens of digits for fun, often with little rhymes or sentences where each word's length stands for a digit.
Classrooms tend to run with it. Students measure plates, lids and bicycle wheels with string, then divide to see how close they land. Math clubs hold recitation contests. Bakeries and home cooks turn out fruit pies, cream pies and savory pot pies, sometimes with the Greek letter cut into the top crust.
The string and plate experiment works well at a kitchen table. Wrap a string around something round, measure it, divide by the width across, and the answer hovers a bit above three every time, whether the circle is a coin or a cake pan.
Ways to celebrate
- Measure a round plate with string and work out pi yourself.
- Bake a pie and cut the pi symbol into the crust.
- Try memorizing the first ten digits of pi.
- Share a slice of pie with a neighbor or coworker.
- Look for circles around the house and guess their circumference.
Things for the day
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Dates
| Year | Date |
|---|---|
| 2026 | Saturday, March 14 |
| 2027 | Sunday, March 14 |
| 2028 | Tuesday, March 14 |
| 2029 | Wednesday, March 14 |
| 2030 | Thursday, March 14 |