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

According to the Mayo Clinic, most healthy adults can safely consume up to 400 mg of caffeine each day. But while most 12-ounce cups of coffee contain somewhere between 90 and 120 mg of caffeine, one 12-ounce "tall" or small cup of Starbucks is far stronger, with about 260 mg of caffeine per cup.

These tiny bottles, or "shots," contain nearly the same amount of caffeine as a cup of Starbucks, which in reality is closer to 4 cups of regular coffee. Each 2-ounce shot has about 215 mg of caffeine.

Unlike Starbucks coffee, McDonald's drip contains roughly the same amount of caffeine as a "standard" cup of Joe. Each 12-ounce cup has about 109 mg of caffeine.

While there's lots of info out there about how bad energy drinks are for you, a single 8-ounce can of Red Bull contains 80 mg of caffeine, less than the a standard cup of coffee and roughly three times fewer caffeine than in a 12-ounce Starbucks coffee. It also contains other ingredients, however, like taurine, whose long term effects have yet to be studied extensively.

You might be surprised to learn that not all tea is designed to lull you into a relaxed, sleepy state. An average cup of brewed black tea contains about 67 mg of caffeine, still less than a can of Red Bull or a cup of McDonald's coffee, but far from minimal.

One 12-ounce can of Coke has 34 grams of caffeine. While that might seem pretty low, if you're like us and drink a few of these throughout the course of the day, it can add up! Still, a single can is the rough equivalent of about a third of a cup of regular coffee or about a seventh of a cup of Starbucks.

A standard shot of espresso contains about 71 mg of caffeine, meaning that a small latte (espresso plus steamed milk) or cappuccino (espresso plus milk and foam) — so long as its made with a single shot — contains the same amount.