One cup of coffee 8 oz. Can contain 95 to 200 mg of caffeine. Various factors can cause the caffeine content to fluctuate from one day to the next, such as the roasting and grinding process and the time it takes to brew it. A cup of instant coffee contains slightly less caffeine, between 27 and 173 mg. Even a cup of decaffeinated brewed or instant coffee contains small amounts of caffeine, from 2 to 12 mg.
Coffee contains higher amounts of caffeine than a cup of black tea, which contains between 40 to 120 mg, but both coffee and black tea are higher than many popular soft drinks, according to MayoClinic.com. A 12 oz. can of Coca-Cola Classic or Coke Zero contains 35 mg of caffeine, while the same serving of Dr. Pepper contains 42 to 44 mg. Pepsi contains 36 to 38 mg. A cup of coffee even contains more caffeine than the popular energy drink Red Bull, which has 76 mg of caffeine for every 8.3 oz. serving.
- Espresso, Single Shot – 29-100 mg (often around 75 mg)
- Espresso, Double Shot (Doppio) – 58-185 mg (often around 150 mg)
- Decaf Espresso, Single Shot – about 8 mg
- Decaf Espresso, Double Shot (Doppio) – about 16 mg
- Nespresso Espresso Capsules – 55-65 mg
- Nespresso Lungo Capsules – 77-89 mg
- Caffeine levels in Starbucks Espresso Drinks and Starbucks Iced Espresso Drinks vary