espresso has more caffeine than Pepsi on both counts: 63mg per 1 oz shot against 38mg per 12 oz can, and about 63mg per fluid ounce against 3. The serving sizes differ, so the table below shows both ways of counting.
These are different categories of drink, which changes how the caffeine arrives. Energy drinks and sodas list an exact number because caffeine is a measured additive; brewed drinks vary with the beans and the brew, so their figures are compiled averages. The numbers here are the standard published values for each.
Pepsi vs espresso: the numbers
| Pepsi | espresso | |
|---|---|---|
| Caffeine per serving | 38mg per 12 oz can | 63mg per 1 oz shot |
| Caffeine per fl oz | 3.2mg | 63.0mg |
| Servings to reach 400mg (FDA context) | 10.5 | 6.3 |
Sources: Pepsi's figure is verified in our Pepsi caffeine guide against Caffeine Informer (source); espresso's figure is verified in our espresso guide against USDA FoodData Central (source).
The concentration gap is the striking part: espresso packs roughly 20 times the caffeine per ounce. Sipping speed matters at that density; a 1 oz shot finished in minutes hits differently than the same milligrams spread over a slow cup.
Which one should you pick?
Pick Pepsi when you want the lighter dose or a slower ramp, and espresso 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
- Pepsi: the full caffeine guide
- espresso: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
FAQ
Does Pepsi or espresso have more caffeine? espresso: 63mg per 1 oz shot versus 38mg per 12 oz can for Pepsi.
Which is stronger per ounce? espresso, at about 63.0mg per fluid ounce versus 3.2mg for 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.