Pi Day is celebrated on March 14 (3/14) because the first digits of π are 3.14. In 2027, March 14 falls on a Sunday, so most schools will celebrate on Friday, March 12 or Monday, March 15. The day is a rare chance to make math feel playful for teenagers, as long as the activities are more than eating pie.
These 18 Pi Day activities for high school mix real math, history and a little competition. Most need only string, paper plates, a ruler and a calculator.
In this guide6 sections
A few facts to open the lesson
- π is the ratio of a circle’s circumference to its diameter, about 3.14159.
- π is irrational: its decimals never end and never repeat.
- Pi Day was started in 1988 by physicist Larry Shaw at the Exploratorium in San Francisco.
- March 14 is also Albert Einstein’s birthday (1879).
Hands-on math activities
- Measure π. Students measure the circumference and diameter of ten round objects with string and a ruler, divide, and average the results. How close does the class get to 3.14?
- Buffon’s needle. Drop toothpicks on lined paper and use the proportion that cross a line to estimate π. It is a great introduction to probability.
- Pi by darts (Monte Carlo). Randomly place dots in a square with an inscribed circle; the ratio of dots inside estimates π/4. Use a spreadsheet for thousands of points.
- Circle area race. Teams find the area and circumference of objects around the room using real measurements.
- Pizza math. Compare the area of one 16-inch pizza with two 12-inch pizzas. Which is the better deal?
- Radian paper plates. Students wrap string the length of a radius around a plate to see what one radian looks like.
Competitions and games
- Digit memorization contest. Who can recite the most digits of π? Teach chunking as a memory strategy, the same idea behind active recall.
- Pi-ku poems. Haiku-style poems with 3, 1 and 4 syllables per line.
- Circle review game. A quiz show on geometry content. See our classroom quiz games.
- Pi scavenger hunt. Find “3.14” or circle formulas hidden around the room, each with a problem to solve.
- Mental math relay. Quick circle problems with a timer. Our mental math tricks help.
- Logic puzzle break. A math-themed puzzle from our logic puzzles for teens.
History and cross-curricular activities
- History of π. Groups research how Archimedes estimated π with polygons, and how estimates improved over time.
- Archimedes’ polygon method. Draw regular polygons inside and outside a circle and compare their perimeters.
- π in science. Find π in formulas for pendulums, waves or planetary orbits.
- Pi Day art. Create a “pi skyline” bar graph where each digit is a building’s height.
- Einstein birthday connection. A short reading on Einstein’s life and one idea he is known for.
- Pi in nature and design. Students photograph or sketch circles in architecture, nature and engineering.
Planning table
| Time available | Best picks |
|---|---|
| 10–15 minutes | Digit contest, pi-ku poems, mental math relay |
| One class period | Measure π, pizza math, Buffon’s needle |
| Two periods | Monte Carlo spreadsheet + history of π research |
Frequently asked questions
When is Pi Day 2027?
Pi Day is March 14, 2027, which falls on a Sunday. Many schools will celebrate on Friday, March 12 or Monday, March 15.
What do high school students do on Pi Day?
Popular activities include measuring π with real objects, estimating π with probability experiments, digit memorization contests and circle-themed review games.
Why is π irrational?
π cannot be written as a fraction of two whole numbers, so its decimal expansion never ends or repeats. This was proven by Johann Heinrich Lambert in the 1760s.
Choose one hands-on activity, one competition and one history connection. Pi Day becomes a math lesson students remember, and yes, you can still bring the pie.
