How many ounces should be in a glass of wine?

According to the USDA, a glass of wine should be 5 ounces. Since a standard bottle contains a little more than 25 ounces, one bottle contains about five glasses of wine. Experts believe that a glass with a large bowl allows the aromas to escape more easily and gives the wine more aromatic complexity. A glass with a small bowl concentrates those aromas and heightens the wine's intensity.

Source: All Recipes