How Shrimp Sizes Work

Picture this: You’re about to make a delicious shrimp dish like Shrimp Étoufée or Coconut Shrimp, and the recipe calls for small, medium, or large shrimp. Sounds easy, right? But when you get to the supermarket, the bags of frozen shrimp you find there often don’t have the sizes labeled on the bag. Instead, you’re looking at numbers like 16/20, 21/30, or 31/35. The same goes for fresh shrimp; depending on where you are buying, some seafood markets will display these same mysterious numbers. Though it’s not exactly obvious, this shrimp sizing system is easy to decode. Here’s everything you need to know about shrimp sizes and counts.

Decoding the shrimp count

The numbers on bags of frozen shrimp refer to its shrimp count, the approximate number of shrimp you’re getting per pound, which is how shrimp size is measured in the United States. The slash indicates the range: 16/20 means between 16 and 20 shrimp per pound.

How shrimp count translates to size

Shrimp comes in small, medium, large, jumbo, and colossal sizes. According to the New York Fulton Fish Market, a 16/20 range represents colossal shrimp, likely the largest you’ll find in a store. Colossal shrimp can also be labeled with a “U” (meaning “under”). For instance, a bagel labeled “U-10” indicates that there are under 10 shrimp in a one pound bag.

Here’s how the sizes break down: