Rockstar Original has more caffeine than brewed black tea on both counts: 160mg per 16 oz can against 47mg per 8 oz cup, 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 brewed black tea: the numbers
| Rockstar Original | brewed black tea | |
|---|---|---|
| Caffeine per serving | 160mg per 16 oz can | 47mg per 8 oz cup |
| Caffeine per fl oz | 10.0mg | 5.9mg |
| Servings to reach 400mg (FDA context) | 2.5 | 8.5 |
Sources: Rockstar Original's figure is verified in our Rockstar Original caffeine guide against Rockstar product page (source); brewed black tea's figure is verified in our brewed black tea guide against USDA FoodData Central (source).
Which one should you pick?
Pick brewed black tea 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
- brewed black tea: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
FAQ
Does Rockstar Original or brewed black tea have more caffeine? Rockstar Original: 160mg per 16 oz can versus 47mg per 8 oz cup for brewed black tea.
Which is stronger per ounce? Rockstar Original, at about 10.0mg per fluid ounce versus 5.9mg for brewed black tea.
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.