Pepsi has more caffeine than Big Red: 38mg vs 34mg in the same 12 oz can. That is a 4mg gap, and since the cans match, the per-serving number is the whole story.
Pepsi vs Big Red: the numbers
| Pepsi | Big Red | |
|---|---|---|
| Caffeine per serving | 38mg per 12 oz can | 34mg per 12 oz can |
| Caffeine per fl oz | 3.2mg | 2.8mg |
| Servings to reach 400mg (FDA context) | 10.5 | 11.8 |
Sources: Pepsi's figure is verified in our Pepsi caffeine guide against Caffeine Informer (source); Big Red's figure is verified in our Big Red guide against Caffeine Informer (source).
Which one should you pick?
Pick Big Red when you want the lighter dose or a slower ramp, and Pepsi when you actually need the bigger hit and know your tolerance. If you are stacking either with other caffeinated drinks through the day, run the math against the 400mg reference rather than guessing.
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
FAQ
Does Pepsi or Big Red have more caffeine? Pepsi: 38mg per 12 oz can versus 34mg per 12 oz can for Big Red.
Which is stronger per ounce? Pepsi, at about 3.2mg per fluid ounce versus 2.8mg for Big Red.
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