Rockstar Original has more caffeine than Mountain Dew Zero Sugar on both counts: 160mg per 16 oz can against 68mg per 12 oz can, and about 10mg per fluid ounce against 6. 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.
Rockstar Original vs Mountain Dew Zero Sugar: the numbers
| Rockstar Original | Mountain Dew Zero Sugar | |
|---|---|---|
| Caffeine per serving | 160mg per 16 oz can | 68mg per 12 oz can |
| Caffeine per fl oz | 10.0mg | 5.7mg |
| Servings to reach 400mg (FDA context) | 2.5 | 5.9 |
Sources: Rockstar Original's figure is verified in our Rockstar Original caffeine guide against Rockstar product page (source); Mountain Dew Zero Sugar's figure is verified in our Mountain Dew Zero Sugar guide against PepsiCo product facts (source).
Which one should you pick?
Pick Mountain Dew Zero Sugar when you want the lighter dose or a slower ramp, and Rockstar Original 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
- Rockstar Original: the full caffeine guide
- Mountain Dew Zero Sugar: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
FAQ
Does Rockstar Original or Mountain Dew Zero Sugar have more caffeine? Rockstar Original: 160mg per 16 oz can versus 68mg per 12 oz can for Mountain Dew Zero Sugar.
Which is stronger per ounce? Rockstar Original, at about 10.0mg per fluid ounce versus 5.7mg for Mountain Dew Zero Sugar.
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.