Diet Pepsi has more caffeine than Vanilla Coke: 35mg vs 34mg in the same 12 oz can. That is a 1mg gap, and since the cans match, the per-serving number is the whole story.
Diet Pepsi vs Vanilla Coke: the numbers
| Diet Pepsi | Vanilla Coke | |
|---|---|---|
| Caffeine per serving | 35mg per 12 oz can | 34mg per 12 oz can |
| Caffeine per fl oz | 2.9mg | 2.8mg |
| Servings to reach 400mg (FDA context) | 11.4 | 11.8 |
Sources: Diet Pepsi's figure is verified in our Diet Pepsi caffeine guide against Caffeine Informer (source); Vanilla Coke's figure is verified in our Vanilla Coke guide against Caffeine Informer (source).
Which one should you pick?
Pick Vanilla Coke when you want the lighter dose or a slower ramp, and Diet 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
- Diet Pepsi: the full caffeine guide
- Vanilla Coke: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
FAQ
Does Diet Pepsi or Vanilla Coke have more caffeine? Diet Pepsi: 35mg per 12 oz can versus 34mg per 12 oz can for Vanilla Coke.
Which is stronger per ounce? Diet Pepsi, at about 2.9mg per fluid ounce versus 2.8mg for Vanilla Coke.
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.