The lightest dark chocolate band
USDA measures chocolate in the 45 to 59% cacao range at 43 mg of caffeine per 100 g, which comes to about 12 mg in a 1 oz piece. That’s roughly half of USDA’s figure for 60 to 69% dark chocolate (86 mg per 100 g) and about half of 70 to 85% dark chocolate (80 mg per 100 g), in line with the general pattern that more cocoa solids means more caffeine.
Still well above milk chocolate
Even at the low end of the dark chocolate range, this band carries more than double USDA’s figure for milk chocolate (20 mg per 100 g), since it has more cocoa solids and less milk than a standard milk chocolate bar.
A common starting point for “semisweet”
This band covers a lot of what gets sold as semisweet or bittersweet baking chocolate, alongside eating bars in the same percentage range. Because USDA reports bands rather than individual products, a specific bar’s real cacao content and caffeine can sit anywhere within, or close to, this range depending on the manufacturer’s exact recipe.
Where it fits in a day
An ounce, 12 mg, is a small fraction of the 400 mg daily figure the FDA cites for healthy adults; even a whole 3.5 oz bar stays under 150 mg. It matters more for children, whose smaller daily allowances make a few squares a bigger share of the day, and the FDA notes that chocolate’s naturally occurring caffeine doesn’t have to appear on the ingredient list the way added caffeine does.