How many egg whites in one measuring cup?

You can't directly equate egg whites to a specific measurement in a measuring cup. Here's why:

* Egg size varies: Eggs come in different sizes (small, medium, large, extra-large). This means the amount of egg white per egg will vary.

* Egg white density varies: Even within the same size egg, the density of the egg white can differ.

* Whipping affects volume: When you whip egg whites, their volume increases significantly.

Instead of using a measuring cup, it's better to measure egg whites by weight or number of eggs.

* Weight: For most baking recipes, egg whites are measured in grams or ounces.

* Number of eggs: Many recipes will tell you exactly how many egg whites you need.

If you absolutely need to estimate using a measuring cup:

* 1 large egg white: Roughly 1/4 cup

* 2 large egg whites: Roughly 1/2 cup

* 4 large egg whites: Roughly 1 cup

However, these are just estimations. For accurate measurements, always weigh or use the number of eggs specified in the recipe.