A cappuccino is made with espresso coffee, a small amount of steamed milk, and top layer of foamed milk.

Espresso-based drinks at Starbucks generally use the following rule:

One shot in a Tall beverage, two shots in a Grande, and three shots in a Venti.

Caffeine content in coffee can vary enormously due to the length roasting, coffee blend (amount of arabica vs robusta beans), and even extraction length.