caffeine amount in decaf coffee
The average 12-ounce cup of decaf coffee â a Starbucks tall â usually contains between 3 and 18 milligrams of caffeine. (By comparison, an 8.4-ounce can of Red Bull contains 80 milligrams of caffeine) The average of amount of caffeine in regular coffee can vary significantly, usually between 140 and 300 mg. In 2007, Consumer Reports studied cups of decaffeinated coffee from popular chains.