Red Bull wins on total caffeine per serving (80mg per 8.4 oz can, against 63mg for espresso and 34mg for Coca-Cola Classic), but ounce for ounce espresso is the strongest of the three at about 63mg per fluid ounce. The three servings are different sizes, so the ranking flips depending on which number you mean.
espresso vs Red Bull vs Coca-Cola Classic: the numbers
| espresso | Red Bull | Coca-Cola Classic | |
|---|---|---|---|
| Caffeine per serving | 63mg per 1 oz shot | 80mg per 8.4 oz can | 34mg per 12 oz can |
| Caffeine per fl oz | 63mg | 9.5mg | 2.8mg |
| Servings to reach 400mg (FDA context) | 6.3 | 5.0 | 11.8 |
Sources: espresso is 63mg per 1 oz shot per USDA FoodData Central SR Legacy 171891, 212mg per 100g times 30g (source), and the figure is carried in our espresso guide; Red Bull is 80mg per 8.4 oz can per Caffeine Informer (source), and the figure is carried in our Red Bull guide; Coca-Cola Classic is 34mg per 12 oz can per Caffeine Informer (source), and the figure is carried in our Coca-Cola Classic 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:
- espresso vs Red Bull, head to head
- espresso vs Coca-Cola Classic, head to head
- Red Bull vs Coca-Cola Classic, head to head
Which one should you pick?
Take Coca-Cola Classic when you want the smallest dose of the three, espresso when you want a middle number without thinking about it, and Red Bull when you actually want the 80mg 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, espresso, Red Bull or Coca-Cola Classic? Red Bull, at 80mg per 8.4 oz can. espresso has 63mg per 1 oz shot and Coca-Cola Classic has 34mg per 12 oz can.
Which of the three is strongest per ounce? espresso, at about 63mg per fluid ounce, ahead of Red Bull at 9.5mg and Coca-Cola Classic at 2.8mg.
How many Red Bull servings reach the FDA 400mg reference? About 5.0 of them, at 8.4 oz can 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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