The amount of caffeine in coffee can vary depending on factors such as the type of coffee bean, the brewing method, and the serving size. On average, an 8-ounce (240-milliliter) cup of brewed coffee contains approximately 95 milligrams of caffeine. However, this amount can range from about 70 to 140 milligrams depending on various factors. Specialty coffees like espresso typically contain higher concentrations of caffeine per ounce compared to regular brewed coffee. It's important to note that caffeine content can also vary based on the brand and specific preparation methods.