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

These tiny bottles, or "shots," contain nearly the same amount of caffeine as a cup of Starbucks, which is closer to four 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 a standard cup of coffee and roughly one-third of the caffeine 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 in a 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.