Here's what the maximum amount of caffeine you should be drinking in a day looks like

And you thought Red Bull was bad.

It turns out that while a can of the energy drink has 80 milligrams of caffeine, a small cup of Starbucks drip coffee has more than three times that amount.

Since many beverages don't show their caffeine content, it can be tough to make sure you're not overdoing it — and the Mayo Clinic advises adults to limit their caffeine intake to 400 mg per day. More than that and you run the risk of unpleasant side effects ranging from migraine headaches to irritability, upset stomach, and even muscle tremors.

With that in mind, here's what the maximum amount of caffeine you should be drinking in a day looks like in the context of your favorite beverages, from McDonald's coffee to soda, tea, and energy shots:

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Starbucks coffee

The Mayo Clinic maintains that most healthy adults can safely consume up to 400 mg of caffeine each day. Starbucks ultra-strong coffee would put you over that limit with just two cups. In contrast, most other coffee only contains about 90-120 mg of caffeine per cup. A single small cup of Starbucks' Blonde Roast coffee, on the other hand, has 270 mg of caffeine.

5-Hour Energy

Energy shots might look tiny, but they can pack a surprisingly powerful caffeine punch. One 5-Hour-Energy contains 200 mg of caffeine — nearly the same amount as a cup of Starbucks.

McDonald's coffee

Unlike Starbucks coffee, McDonald's drip offers roughly the same amount of caffeine as a "standard" cup of joe, according to the folks over at CaffeineInformer.com. The chain does not currently report the amount of caffeine in its coffee, but Caffeine Informer says each 12-ounce cup has 109 mg of caffeine.