Dark chocolate does contain caffeine because natural cocoa solids inherently carry small amounts of this plant compound. A standard one ounce serving of dark chocolate typically contains around twenty milligrams of caffeine depending on the cocoa percentage. Higher cocoa percentages mean more cocoa solids and slightly higher caffeine levels per serving. While the caffeine amount is much lower than a cup of coffee, sensitive individuals may still notice a mild energy boost. Enjoying dark chocolate earlier in the day prevents potential sleep disruptions.