Onion Sizes Explained

Recipes often call for “medium” onions. What does “medium” mean in terms of volume and weight?

While we usually give weights for ingredients like meats and poultry, cheeses, and baking ingredients, we tend to call for vegetables in terms of relative size unless the weight is of utmost importance to the outcome of a particular recipe. But since produce sizes can vary (especially due to seasonality), we set standards for all our recipe development and testing. Our default onion is a medium yellow cooking onion (like the ones you find in net bags in the grocery store), which is the approximate size of a tennis ball. Here’s how small, medium, and large onions measure up.

SMALL ONION: Like a billiard ball

WEIGHT: 6 ounces

VOLUME: 3/4 cup chopped

MEDIUM ONION: Like a tennis ball

WEIGHT: 8 ounces

VOLUME: 1 cup chopped

LARGE ONION: Like a softball

WEIGHT: 16 ounces

VOLUME: 1 1/2 cups chopped

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