A typical cup of coffee contains about 95 to 165 milligrams (mg) of caffeine, depending on various factors such as the brewing method, type of coffee bean, and cup size. For example, an 8-ounce (240 ml) brewed coffee generally has around 95 to 135 mg of caffeine, while a 12-ounce cup may have 113 to 247 mg. Espresso contains about 70 to 130 mg per shot, which is a smaller volume but higher caffeine concentration. Decaffeinated coffee contains much less caffeine, usually 0 to 15 mg per cup. The caffeine content can vary significantly with robusta beans having roughly twice the caffeine compared to arabica beans, and cold-brewed coffee often having higher caffeine due to extended brewing time.