brewed coffee has the most caffeine of the three: 95mg per 8 oz cup, against 80mg per 8.4 oz can for Red Bull and 28mg per 8 oz cup for brewed green tea. It also leads per ounce, at roughly 11.9mg to 3.5mg, so the order holds whichever way you count.
brewed green tea vs brewed coffee vs Red Bull: the numbers
| brewed green tea | brewed coffee | Red Bull | |
|---|---|---|---|
| Caffeine per serving | 28mg per 8 oz cup | 95mg per 8 oz cup | 80mg per 8.4 oz can |
| Caffeine per fl oz | 3.5mg | 11.9mg | 9.5mg |
| Servings to reach 400mg (FDA context) | 14.3 | 4.2 | 5.0 |
Sources: brewed green tea is 28mg per 8 oz cup per USDA FoodData Central SR Legacy 171917, 12mg per 100g times 237g (source), and the figure is carried in our brewed green tea guide; brewed coffee is 95mg per 8 oz cup per USDA FoodData Central SR Legacy 171890, 40mg per 100g times 237g (source), and the figure is carried in our the caffeine database; Red Bull is 80mg per 8.4 oz can per Caffeine Informer (source), and the figure is carried in our Red Bull guide.
Why the three numbers are not measured the same way
Canned drinks list an exact figure because caffeine is a measured ingredient, so the number on the label is the number in the can. Brewed drinks are averages: grind, dose, water temperature and steep time move a cup of coffee or tea by tens of milligrams either way. When you compare across those categories, treat the canned figures as fixed and the brewed ones as a center point with real spread around it.
The three head-to-head pages
Each pairing has its own page with the full math:
- brewed green tea vs brewed coffee, head to head
- brewed green tea vs Red Bull, head to head
- brewed coffee vs Red Bull, head to head
Which one should you pick?
Take brewed green tea when you want the smallest dose of the three, Red Bull when you want a middle number without thinking about it, and brewed coffee when you actually want the 95mg and know how you handle it. If you drink more than one caffeinated thing a day, the useful move is adding the day up against the 400mg reference rather than judging each drink alone.
For context, the FDA cites 400mg of caffeine a day as an amount generally not associated with negative effects in healthy adults. Tolerance and health vary, so treat these numbers as information, not advice.
Related reading
- The verified caffeine database
- Every drink compared: the comparisons index
- Compare any two of 120+ drinks
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FAQ
Which has the most caffeine, brewed green tea, brewed coffee or Red Bull? brewed coffee, at 95mg per 8 oz cup. Red Bull has 80mg per 8.4 oz can and brewed green tea has 28mg per 8 oz cup.
Which of the three is strongest per ounce? brewed coffee, at about 11.9mg per fluid ounce, ahead of Red Bull at 9.5mg and brewed green tea at 3.5mg.
How many brewed coffee servings reach the FDA 400mg reference? About 4.2 of them, at 8 oz cup each. The FDA cites 400mg a day as an amount generally not associated with negative effects in healthy adults. This is information, not advice.
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