# Pi Day Quiz: How many digits can you name?

BY Frank Bi  March 14, 2014 at 11:04 AM EDT

It’s National Pi Day. How many digits of the mathematical constant can you name?

It’s Pi Day – the day that math geeks across the globe collectively pause to celebrate the first three digits of pi, or 3.14.

The mathematical constant, which is the ratio of a circle’s circumference to its diameter, can be used to find the area or circumference of a circle — along with that of the pie you’re hopefully enjoying right now.

Designated as a U.S. holiday in 2009, National Pi Day is celebrated in elementary schools, science museums and pizza parlors. In coffee shops and tech companies and public television newsrooms.

And we wanted to know, how many decimal spots can you memorize?

Because pi is an irrational number — meaning the numbers never end and never fall into a repeating pattern — Pi Day is also celebrated with pi recitation contests. On Pi Day 2013, the winner of one such recitation contest held by the math department at Harvard University was able to recite pi to 224 digits.

Try our pi tester above. Along the way you’ll find out some fun facts about the elusive number. And type in your birthday to see where the digits fall in pi.

PBS NewsHour challenged people on the streets of Washington D.C. to see how many digits of pi they could recall. We also spoke to math experts at the Mathematical Association of America to learn more about the irrational number.