Here's how In-N-Out turned a $4 burger into a cult favorite and now brings in $2 billion a year.

In-N-Out Burger, a California-based burger chain, has gained a cult following with its "animal-style" fries and double-double burgers, despite not being as globally recognizable as McDonald's golden arches.

The company, founded in 1948 by Harry and Esther Snyder as a single drive-through hamburger stand in Baldwin Park, California, has grown to just over 400 locations and is estimated to be the ninth largest burger chain in the U.S. by sales. It generates an estimated $2.1 billion annually, according to food service consulting firm Technomic.

According to Kevin Schimpf, a director of industry research at Technomic, the chain's ability to achieve high sales with a limited number of locations is truly remarkable. He notes that the chain has the highest sales per store in the burger segment.

The company, renowned for its fresh-to-order burgers, is present in eight states, primarily on the west coast. As a result of its dedication to never freezing ingredients, each restaurant must be within a day's drive of one of its supply centers.

In-N-Out has kept prices low despite inflation, with a basic burger only increasing by 25% since 2020, which is the lowest increase among nine burger joints studied by Technomic.

In 2017, at the age of 35, Lynsi Snyder, the granddaughter of Harry and Esther, took over the private company that had never been franchised and became one of the world's youngest billionaires, according to Forbes.

In-N-Out's starting wages for employees are above industry average, and managers can earn well into the six figures. The company also landed a top 10 spot on Glassdoor's inaugural Best-Led Companies list earlier this year.

In-N-Out Burger has found a way to balance profit without compromising on quality, according to Stacy Perman, author of "In-N-Out Burger: A Behind-the-Counter Look at the Fast-Food Chain That Breaks All the Rules."

Perman believes that they have defined success on their own terms, which may be their greatest legacy.

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