According to lab tests, they're the same. Though their packaging shows Pepsi has a slightly higher caffeine content.
Coca-Cola has 34.5 milligrams of caffeine and Pepsi has 37.5 milligrams of caffeine.
Diet CokeDiet Pepsi
Diet Coke is stronger by about 10 milligrams more than Diet Pepsi.
Diet Coke has 46.5 milligrams of caffeine per can and Diet Pepsi has 36 milligrams.
Pepsi One actually has the most caffeine out of any popular, non-energy drink soda.
Pepsi One has 54 milligrams of caffeine per can and Tab has 46.4 mg of caffeine per can.
Faygo ColaRC Cola
If you're trying to stay awake at the Gathering of the Juggalos, look for an RC Cola or even a Shasta — both have more caffeine than Faygo.
RC Cola has 45.2 milligrams of caffeine per can and Faygo Cola has 41.7 milligrams of caffeine per can.
Starbucks Double EspressoTall Starbucks Coffee
Sorry, espresso fiends, if you're looking for the most caffeine per fluid ounce at Starbucks, your best bet is a regular cup of coffee.
A Starbucks double espresso has 150 milligrams of caffeine and a tall Starbucks Coffee has 260 milligrams of caffeine.
Starbucks Single EspressoVenti Tazo Green Tea Latte
If you've got the choice between a shot of espresso and a green tea latte to settle your caffeine fix, green tea is your better bet.
A venti Tazo Green Tea Latte has 110 milligrams of caffeine and a Starbucks single espresso has 75 milligrams of caffeine.
Tall Starbucks CoffeeMedium Dunkin Donuts Coffee
A medium Dunkin Donuts coffee might have two more ounces of liquid than its Starbucks equivalent, but it's actually no where near it in terms of caffeine content. Starbucks has almost 100 more milligrams of caffeine.
A medium Dunkin Donuts Coffee has 178 milligrams of caffeine and a tall Starbucks Coffee has 260 milligrams of caffeine.
Dunkin Donuts Double EspressoStarbucks Double Espresso
Starbucks beats Dunkin Donuts by more than 50 milligrams when comes to double shots.
A Dunkin Donuts double espresso has 97 milligrams of caffeine and a Starbucks double espresso has 150 milligrams of caffeine.
Medium Dunkin Donuts Iced CoffeeTall Starbucks Iced Coffee
A 12-ounce iced coffee from Starbucks has about 30 milligrams more than a 24-ounce iced coffee from Dunkin Donuts.
A medium Dunkin Donuts Iced Coffee has 91 milligrams of caffeine and a tall Starbucks Iced Coffee has 120 milligrams of caffeine.
Medium McDonalds CoffeeMedium Tim Hortons Coffee
This one is a little tricky, but a 16-ounce medium coffee from McDonalds has 5 milligrams more than a 14-ounce medium coffee from Tim Hortons. So in terms of caffeine per ounce, so they're about the same.
A medium McDonalds Coffee has 145 milligrams of caffeine and medium Tim Hortons Coffee has 140 milligrams of caffeine.
Medium Iced McDonalds CoffeeMedium Dunkin Donuts Iced Coffee
If you can't get to a Starbucks and you're looking for something strong, McDonalds is a better replacement in terms of caffeine.
A medium Dunkin Donuts Iced Coffee has 91 milligrams of caffeine and medium Iced McDonalds Coffee has 145 milligrams of caffeine.
Grande Starbucks CoffeeRedline Energy Drink
Redline may look tiny and scary, and compared to other energy drinks it is, but a medium Starbucks beats it by a small amount.
A Redline Energy Drink has 316 milligrams of caffeine and a grande Starbucks Coffee has 330 milligrams of caffeine.
Baskin Robbins Cappuccino Blast5-Hour Energy
Turns out 5-Hour Energy actually has less caffeine than a cappuccino.
A Baskin Robbins Cappuccino Blast has 234 milligrams of caffeine and 5-Hour Energy has 200 milligrams of caffeine.
16-ounce Rockstar Energy Drink8.46-ounce Red Bull
They actually both have pretty much about the same amount of caffeine per fluid ounce.
A 16-ounce Rockstar Energy Drink has 160 milligrams of caffeine and a 8.46-ounce of Red Bull has 80 milligrams of caffeine.
Snapple TeaSoBe Green Tea
Weirdly enough, even though SoBe comes in a slightly bigger bottle, Snapple will give you a little more caffeine.
A Snapple Tea has 42 milligrams of caffeine and has a SoBe Green Tea has 35 milligrams of caffeine.
Do You Know Which Drink Has More Caffeine In It?
Caffeine counts come from Caffeine Informer's Caffeine Database.