Pi Day is an annual national celebration of the mathematical concept, which is the ratio of a circle's circumference to its diameter and equals 3.14...
March 14 is also reportedly the birthday of theoretical physicist Albert Einstein.
On Thursday, restaurants and businesses nationwide will be celebrating one of the "nerdiest" days of the year with deals on actual pie, pizza pie and other delights.
Here are some of the deals you can take advantage of this Pi Day:
Get top local stories in DFW delivered to you every morning. Sign up for NBC DFW's News Headlines newsletter.
Traditional Pie
Marie Callender's
Get $3.14 off select Marie Callender’s frozen multi-serve dessert pies when shopping online at select retailers, including Walmart, Kroger and Amazon Fresh. Go to the Marie Callender's website to get the offer on Thursday, March 14 (while supplies last).
Polly's Pies
Polly's Pies, a Southern California-based restaurant and bakery chain, will give a free slice of pie to customers who dine-in and purchase an entrée.
Pies are also available for nationwide shipping.
Walmart
Walmart and drone delivery company Wing will send customers in parts of the Dallas-Fort Worth area 2 mini pies for free!
Customers must be eligible for Wing drone delivery (check your address at wing.com/walmart), and must place orders via the Wing Drone Delivery app. The service is currently available in the cities of Frisco and Lewisville.
Pizza Pie
7-Eleven
7-Eleven is offering members of its loyalty programs a large pizza for $3.14 in 7-Eleven, Speedway and Stripes stores on Thursday, March 14. (Limit one per transaction, two per day.)
For delivery orders through the 7Now app, get free delivery with a purchase of $15 or more or get $14 off a purchase of $30 or more using the promo code PIDAYDEAL (Limit one offer per customer, limited pickup and delivery area.)
Anthony's Coal Fired Pizza & Wings
Get a 12-inch cheese pizza for $3.14 with the purchase of any beverage on Thursday, March 14, at Anthony's Coal Fired Pizza & Wings. Valid for dine-in only.
BJ's Restaurant & Brewhouse
Get a mini one-topping pizza for $3.14 on Thursday, March 14, at BJ’s Restaurant & Brewhouse. Valid for dine-in only.
Blaze Pizza
You can get an 11-inch pizza for just $3.14 at participating Blaze Pizza locations on March 14. The in-store-only offer is one per person and valid on any original dough pizza. An upcharge for specialty crusts like gluten-free and cauliflower will apply. Check the list for non-participating restaurants.
California Pizza Kitchen
Sign up for California Pizza Kitchen's CPK Rewards loyalty program to get a $3.14 pizza (choose from Original BBQ Chicken Pizza, Pepperoni, or Traditional Cheese), with a $25 minimum purchase for dine-in only.
Current rewards members will find this offer in their digital wallet on March 14.
DIGIORNO
Starting on Pi Day, March 14 and ending on April 11, if you experience a pizza delivery or carry-out fail, you can upload an image to DiGiornoPizzaRescue.com and receive a DIGIORNO pizza coupon.
"AI-enabled pizza technology will assess the pie for its level of mishap, which will then unlock a digital coupon based on the percentage of pizza that's been damaged," a press release stated. (0-30% damage - $1 off, 31-60% damage - $1.50 off and 60-100% damage - $2 off) *. People can then redeem the coupon at the grocery or supermarket of their choice and pick up a DIGIORNO pizza.
Little Caesar's
Get $3.14 off any pizza on Thursday only with the code PIZZAPI.
Pieology
Members of Pieology's Pie Life Rewards loyalty program will get two free perks on Thursday, March 14, when they order a Create Your Own (CYO) Pizza or Calzone. Perks include cookies, drinks and salad. Offer good in-store and online, through the Pie Life Rewards App or at Pieology.com.
The Pizza Press
At The Pizza Press for the entire month of March, when you buy any pizza, you can get a second signature pizza for $3.14 in honor of Pi Day.
Other
Burger King
Members of Burger King's Royal Perks program can enjoy a free Hershey’s Sundae Pie with any purchase of $3.14 or more all day Thursday.
The offer must be activated in the “Offers” tab on the BK App or on bk.com before placing an order.
Keebler
Enter for a chance to win a Pi (e) day prize pack by liking their Instagram post and tagging a friend using #KeeblerPieDayEntry. No purchase necessary.
Krystal
Krystal customers who make an online purchase of $10 or more will get $3.14 off their order on March 14.
Starbucks
Select accounts will have a BOGO deal - Free handcrafted drink when you buy one from 12-6 p.m. on Thursday.
Taco Bell
Taco Bell is selling their Mexican Pizzas for $3.14 on Pi Day. The offer limited to one per customer, only in the app.
