Birthdays are pretty special so Krispy Kreme is making sure everyone gets to share in its extra-sweet celebration when the chain turns 81 on Friday, July 27.

The doughnut maker is marking the occasion by offering a dozen of its original glazed doughnuts for just $1 for one day only, but of course there's a little catch — you have to buy a dozen doughnuts at the regular price first.

Prices for a dozen doughnuts vary across the country, but at most Krispy Kremes, you'll be able to treat coworkers, family and friends (or just yourself!) for about $7 to $8 a box.

Last year, Krispy Kreme celebrated its 80th birthday by incentivizing customers with an even sweeter deal, offering a dozen doughnuts for just 80 cents to any customer who purchased a dozen doughnuts at the retail price. And in 2015, they celebrated a fictional holiday, “Day of The Dozens,” on Dec. 12 by offering a free box of 12 doughnuts to any customer who purchased a dozen.

Sure, those doughnuts are irresistible but how are they so stinkin' cheap? Is the chain constantly losing money on these deals?

“Typically, the more volume we buy as a restaurant or restaurant group, the cheaper we can get ingredients,” Joe LoNigro, executive chef at Otto’s Tacos and the forthcoming restaurant Brine Chicken in New York City, told TODAY Food.

LoNigro, who oversees ordering all of the ingredients at five of his restaurants, explained that if eateries are buying ingredients in bulk, it saves the shop a lot of money in long run. He estimated that it costs the chain no more than 20 cents per pastry to produce its irresistibly light doughnuts.

“Doughnuts, in general, are made with some of the cheapest ingredients,” said LoNigro. That includes pantry staples like sugar, flour, yeast and salt — and not much else ... unless the doughnut is a fancier flavor, like Oreo Cookies and Creme.

“The most expensive ingredients on a doughnut are usually the toppings,” continued LoNigro, who noted that fillings make pastries more costly, too.

Since Krispy Kreme is making a much larger profit on the first box, they aren’t just breaking even by offering this promotion: they’re still coming out on top. It’s a win-win for the brand, as well as any customer with a major sweet tooth.

But just because the original glazed doughnuts are having their day in the spotlight this Friday, it doesn’t mean that customers can’t buy other decorated breakfast bites.

On Friday, the chain is debuting a limited-edition confection: a special Glazed Confetti Doughnut, that will be available from July 27 to Aug. 2. It’s made with birthday-cake flavored dough, then topped with plenty of sprinkles and the original glaze.

Happy birthday, Krispy Kreme!