An average 8–ounce (oz) cup of coffee contains around 80–100 milligrams (mg) of caffeine. However, the caffeine content can vary considerably depending on several factors such as coffee type ...

It's generally safe to drink about four 8-ounce (oz) cups of coffee, which contain about 400 milligrams (mg) of caffeine, per day. More than this amount might be too much. You may feel anxious ...