How much caffeine is in a cup of coffee?
A typical 8-ounce (240 ml) cup of brewed coffee has about 80 to 100 milligrams of caffeine. A single espresso shot has about 60 to 75 mg, and decaf usually 2 to 15 mg.
The amount of caffeine varies widely. It depends on the type of bean, how dark the roast is, how finely the coffee is ground and how it is brewed. Robusta beans contain roughly twice as much caffeine as Arabica beans.
Espresso has more caffeine per milliliter than drip coffee, but a shot is small, so it often contains less in total than a full mug. Large coffee-shop drinks can contain 300 milligrams or more.
Comparing drinks
A cup of black tea usually has about 40 to 70 milligrams of caffeine, green tea about 20 to 45 and a 355 ml can of cola about 30 to 40. Energy drinks vary but often contain about 80 to 300 milligrams per can.
Did You Know?
Contrary to popular belief, dark roast coffee does not contain much more caffeine than light roast. Roasting longer can slightly reduce caffeine by weight.