A 12-ounce (355 ml) can of Coca-Cola Classic contains about 34 mg of caffeine. Diet Coke has a higher caffeine content, with approximately 46 mg per 12-ounce can. This is roughly one-third the caffeine content of a typical 8-ounce cup of coffee, which has about 95 mg of caffeine

. In smaller or larger servings, the caffeine content scales roughly proportionally:

• 7.5-ounce can of Coke: about 21 mg caffeine
• 20-ounce bottle of Coke: about 53 mg caffeine
• 7.5-ounce can of Diet Coke: about 28 mg caffeine
• 20-ounce bottle of Diet Coke: about 70 mg caffeine

Diet Coke contains more caffeine than regular Coke because the company adds extra caffeine to give it a distinctively more bitter flavor profile

. In summary, Coke has about 34 mg caffeine per 12-ounce serving, while Diet Coke has about 46 mg caffeine per 12-ounce serving. Both have significantly less caffeine than coffee or many energy drinks