Mello Yello has more caffeine than Diet Pepsi: 51mg vs 35mg in the same 12 oz can. That is a 16mg gap, and since the cans match, the per-serving number is the whole story.
Diet Pepsi vs Mello Yello: the numbers
| Diet Pepsi | Mello Yello | |
|---|---|---|
| Caffeine per serving | 35mg per 12 oz can | 51mg per 12 oz can |
| Caffeine per fl oz | 2.9mg | 4.2mg |
| Servings to reach 400mg (FDA context) | 11.4 | 7.8 |
Sources: Diet Pepsi's figure is verified in our Diet Pepsi caffeine guide against Caffeine Informer (source); Mello Yello's figure is verified in our Mello Yello guide against Caffeine Informer (source).
Which one should you pick?
Pick Diet Pepsi when you want the lighter dose or a slower ramp, and Mello Yello 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
- Diet Pepsi: the full caffeine guide
- Mello Yello: the full caffeine guide
- The verified caffeine database
FAQ
Does Diet Pepsi or Mello Yello have more caffeine? Mello Yello: 51mg per 12 oz can versus 35mg per 12 oz can for Diet Pepsi.
Which is stronger per ounce? Mello Yello, at about 4.2mg per fluid ounce versus 2.9mg for Diet Pepsi.
Comparing caffeine? The caffeine comparison tool puts hundreds of drinks side by side, and the caffeine curfew calculator can check your cutoff time for tonight.