5 fluid ounces of champagne is a standard serving size for a glass. It is about the size of a tennis ball.

In kitchen measures
10 tablespoons
30 tsp · 10 tbsp · 0.625 cups
about the size of a tennis ball
Density estimated by AI from typical values. Champagne typically ranges 0.99–1.01 g/mL depending on how it's packed. A firmly packed scoop weighs more.