A small dose, by coffee’s standards
A 12 fl oz can of Coca-Cola carries 34 mg of caffeine. The Coca-Cola Company’s own FAQ makes the comparison with coffee itself: the same-sized cup of coffee, it says, has 140 mg or more, three to four times as much. USDA’s reference figure for 12 fl oz of drip coffee, 142 mg, agrees.
Among the big colas, Coke is at the low end. Pepsi carries 38 mg per 12 oz can, Pepsi Zero Sugar also 38 mg, and Diet Coke 46 mg. Mountain Dew, at 54 mg, carries more than half as much again as Coke. USDA’s figure for regular cola works out to 33 mg a can, close to Coke’s own number.
Where it adds up
The FDA gives the typical range for caffeinated soft drinks as 23 to 83 mg per 12 fl oz, and Coke sits in the lower part of it. At 34 mg a can, eleven cans stay under the 400 mg a day the FDA cites for healthy adults. For most adults, caffeine is not the reason to limit Coke.
It matters more for children, for whom cola is an easy source of caffeine to overlook. The FDA notes that the Dietary Guidelines for Americans say drinks containing caffeine should be avoided for children younger than two, and that drinks with no added sugars should be the primary choice for children and teens. For a teenager, the calculator on this site sets the limit at 2.5 mg per kg of body weight at its default sensitivity, 125 mg for a 50 kg teen, which three cans of Coke (102 mg) and a 12 oz bottled iced tea (33 mg) already pass.
Caffeine-free options
The Coca-Cola Company sells caffeine-free versions of Coca-Cola, Diet Coke and Coca-Cola Zero Sugar, and lists Sprite, Fresca and Fanta among its caffeine-free drinks. It also says it prints caffeine content near the Nutrition Facts on its cans and bottles, so the label is the quickest check for a flavour not listed here.