4 ounces of feta cheese is a standard serving size for many recipes. It is about the size of a tennis ball when poured into a loose pile.

In kitchen measures
11.8 tablespoons
35.4 tsp · 11.8 tbsp · 0.737 cups
about the size of a tennis ball
Density estimated by AI from typical values. Feta cheese typically ranges 0.55–0.75 g/mL depending on how it's packed. A firmly packed scoop weighs more.