how much caffeine in coffee per cup?
<answer> The caffeine content in a cup of coffee is ranging from 50 to 400+ mg per cup. <context> The active ingredient in coffee is caffeine, the most commonly consumed psychoactive substance in the world . The caffeine content in a cup of coffee is highly variable, ranging from 50 to 400+ mg per cup. A small home-brewed cup of coffee could contain 50 mg, while a big 16 oz Starbucks grande can contain over 300 mg.