The amount of caffeine in coffee can vary depending on the type of coffee bean, the method of brewing, and the serving size. On average, an 8-ounce (240-milliliter) cup of coffee contains about 95 milligrams of caffeine. However, serving sizes can vary greatly, and some cups of coffee may contain as little as 30 milligrams of caffeine, while others may have as much as 200 milligrams or more.
It’s also important to note that the caffeine content of coffee can also vary depending on the brewing method. For example, espresso generally has more caffeine per ounce than brewed coffee, and a cup of instant coffee has less caffeine than brewed coffee or espresso.
Additionally, the caffeine level can also vary between the coffee shop and home-brewed coffee, as the amount of coffee used in each serving can also affect the final caffeine content.