Why Are McDonald's Filet-O-Fish Always Square?

The Filet-O-Fish is a classic staple on the McDonald's menu. Featuring a fried fish patty topped with a slice of cheese and tartar sauce on a hamburger bun, it's a simple sandwich, but despite its simplicity, it's been a fan favorite for years. However, there's one quality about it that has continually perplexed diners: its shape.

Unlike most of the other McDonald's sandwich offerings, the Filet-O-Fish is distinctly square in shape. Customers have guessed the reasons why; a Reddit post asking about the unique shape received a number of speculations, from the ease of cutting to the convenience of packaging and storing square-shaped items.

McDonald's set the rumors to rest and addressed the real reason why the filets are square in a 2022 Facebook post, revealing that the company layers "whole Alaska Pollock filets" into a block. The block then gets cut into smaller squares for consistency so that customers get the same size and shape sandwich every time.

The origins of the Filet-O-Fish date back over 60 years. In 1962, a McDonald's franchisee named Lou Groen wanted to have something to sell to his Catholic customers who couldn't eat meat on Fridays during Lent. Groen spoke to McDonald's corporate, and the company decided to test out a fried fish sandwich alongside another new menu item: the Hula Burger, which had a grilled pineapple slice on it. The sandwich that sold better would make it on the menu.

Between the Filet-O-Fish and the Hula Burger, it was no contest; the Filet-O-Fish outsold the Hula Burger 350 to 6. The sandwich has been on McDonald's menus ever since. Originally it only cost $0.29; nowadays, it costs around $4 with inflation.

Depending on location, you can even find Filet-O-Fish variations, such as the addition of special Old Bay seasoned tartar sauce on sandwiches in certain parts of the United States. In certain Asian countries, such as Singapore, you can even get a sandwich with spicy wasabi sauce.

While the Filet-O-Fish might be the classic fast food fish sandwich, it's certainly not the only one on the market. Plenty of other fast food restaurants have thrown their hats in the ring over the years and tried rivaling McDonald's with their own offerings. Take, for example, the Burger King Fish 'N Crisp — another square-shaped fried fish filet topped with cheese and tartar sauce, much like the Filet-O-Fish.

Wendy's has a limited-time fish sandwich that is only available at certain times of the year. The Crispy Panko Fish Sandwich, featuring yet another square fried fish filet topped with cheese, lettuce, pickles, and tartar sauce, appears on the menu around the Lenten season each year. Wendy's offering has a few more toppings and features a breading made with airy panko breadcrumbs.

Wherever you prefer to go to get your fried fish sandwich, now you know why so many fast food restaurants serve their filets in square form. And you can be sure you'll get the same familiar shape every time.