A standard Hershey's Milk Chocolate bar has about 9 mg of caffeine in the 1.5 oz bar, per Caffeine Informer's chocolate bar entry. That is roughly a tenth of what a cup of drip coffee gives you. Chocolate candy carries caffeine because it is made from cocoa, but the amount in a milk chocolate bar is small. Dark chocolate runs higher, and the little single-piece candies barely register.
Why chocolate has caffeine at all
Cocoa beans naturally contain caffeine along with a related compound called theobromine. The more actual cocoa in the product, the more of both you get. That is why a milk chocolate bar, which is mostly sugar and milk with a smaller cocoa fraction, lands near the bottom, while a dark bar of the same weight can carry two to three times the caffeine. Peanut butter cups and candy-coated pieces dilute the cocoa further with filling, coating, and sugar, so they come in lower per piece.
Hershey used to publish caffeine numbers in a consumer FAQ but stopped maintaining that page, so the figures below come from Caffeine Informer's compiled entries, which is the most consistent public source for these specific products. Treat them as close estimates. Cocoa content shifts slightly between production runs, and caffeine in chocolate is never as tightly controlled as it is in a can of soda.
Caffeine in popular chocolate candy by the piece
| Candy | Serving | Caffeine |
|---|---|---|
| Hershey's Milk Chocolate bar | 1 bar (1.5 oz) | 9 mg |
| Hershey's Special Dark bar | 1 bar (1.45 oz) | 20 mg |
| Hershey's Kiss | 1 piece | 1 mg |
| Reese's Peanut Butter Cup | 1 cup | 4 mg |
| M&M's Milk Chocolate | 1 oz (28 g) | 5 mg |
| M&M's Dark Chocolate | 1 oz (28 g) | ~10 mg |
Sources: Caffeine Informer candy database for the Hershey's bar, Special Dark, Kisses, and Reese's figures, and the M&M's Chocolate Candies entry for the plain and dark M&M's numbers. The dark M&M's figure is an estimate, since cocoa content roughly doubles the caffeine of the milk version per ounce.
For context, the FDA cites 400mg of caffeine a day as an amount generally not associated with negative effects in healthy adults. How caffeine affects you depends on your own tolerance and health, so treat these numbers as information, not advice.
What this means in practice
You would have to eat about 44 Hershey's Milk Chocolate bars to match the 400 mg daily figure the FDA references, or around 100 Hershey's Kisses to reach the caffeine in a single strong coffee. A fun-size trick-or-treat haul is not going to keep an adult awake. The real reason chocolate late at night bugs some people is sugar, not caffeine. Theobromine, the other stimulant in cocoa, is milder and longer acting than caffeine, which is part of why chocolate gives a gentler lift than a coffee of the same weight.
The one place the numbers add up is dark chocolate. A full king-size Special Dark bar, or a couple of the 1.45 oz bars, gets you into the 40 mg range, which is comparable to a can of cola or a shot of weak espresso. If you are sensitive to caffeine and reaching for dark chocolate in the evening, that is the piece to watch. Milk chocolate and the little candies are not worth worrying about. If you are handing candy to kids, the caffeine load across a normal serving is negligible compared to the sugar.
Comparing caffeine? The caffeine comparison tool puts hundreds of drinks side by side, and the caffeine curfew calculator can check your cutoff time for tonight.
Related caffeine reading
- Chocolate caffeine content: dark, milk, and cocoa compared
- How much caffeine is in chocolate milk
- The full Barista Life caffeine database
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Gear from this guide
FAQ
How much caffeine is in a Hershey bar? A standard 1.5 oz Hershey's Milk Chocolate bar has about 9 mg of caffeine, per Caffeine Informer. The Special Dark bar of similar size runs closer to 20 mg because it has more cocoa.
Do Reese's or M&M's have caffeine? A little. A single Reese's Peanut Butter Cup has around 4 mg, and an ounce of milk chocolate M&M's has about 5 mg. Both are low because the cocoa is diluted with filling, coating, and sugar.
Is there enough caffeine in chocolate to keep you awake? Not from milk chocolate or small candies. You would need dozens of bars to approach a cup of coffee. A large dark chocolate serving can reach cola-level caffeine, so that is the only one worth noting at night.
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