Scripps News LifeHolidays and Celebrations


Like infinite digits of pi, there are endless ways to celebrate Pi Day

Over the years, the nerdy holiday has evolved into a significant moneymaker for pie makers and pizza chains nationwide. But how did it all start?
Posted at 2:53 PM, Mar 14, 2024

For pie makers, winter can be brutal. 

"The first two weeks of January, everybody's on a diet. Everybody's on a budget. It's really hard to turn a profit in that first quarter,” said Paula Haney, the owner and chef of Hoosier Mama Pie Company in the Chicago area.

But in recent years, a lifeline has emerged in mid-March: Pi Day. 

"It is our second-biggest day next to Thanksgiving itself," Haney said. 

Pi Day is celebrated each year on March 14 because the date's numbers, 3-1-4 match the first three digits of pi, the never-ending mathematical number. 

"I love that it is so nerdy. We are pi nerds," said Haney, who prepares for the Pi Day frenzy a full month in advance. 

“As soon as Valentine's Day was over, the next day we sat down, wrote up our menu," she said.

Her menu has grown bigger over the years as more Americans eat pie on Pi Day. She says this year “orders are the biggest we’ve ever had.”

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The national holiday was invented by late American physicist Larry Shaw in 1988. Shaw, a former employee of the Exploratorium Museum in San Francisco, came up with the idea during a staff retreat. 

A few years later, his daughter discovered that Pi Day was also Albert Einstein's birthday — and a celebration to his life was added to the festivities.

Today, Pi Day is celebrated in creative ways nationwide by math nerds, educators and dessert lovers. 

At the Children's Museum Houston, there's an annual shaving-cream pie fight, which starts at 1:59 p.m. in a wink to the first few digits of Pi: 3.14159.

Back in Evanston, Illinois, Haney is not just anticipating her busiest Pi Day ever, she's also marking a milestone: She opened her first shop on Pi Day 15 years ago. 

Back then, she says, only a few customers knew about the holiday. Today, she's bracing for a constant stream of pie lovers at her two locations.

"Our goal is to make it until 8 p.m. without running out of pie," she said.

Running out of pies is a possibility for Haney. But the demand for pies?

Like the mathematical constant, that goes on for infinity.