Rockstar Boom has more caffeine than brewed green tea on both counts: 160mg per 16 oz can against 28mg per 8 oz cup, and about 10mg per fluid ounce against 4. 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 Boom vs brewed green tea: the numbers
| Rockstar Boom | brewed green tea | |
|---|---|---|
| Caffeine per serving | 160mg per 16 oz can | 28mg per 8 oz cup |
| Caffeine per fl oz | 10.0mg | 3.5mg |
| Servings to reach 400mg (FDA context) | 2.5 | 14.3 |
Sources: Rockstar Boom's figure is verified in our Rockstar Boom caffeine guide against Caffeine Informer (source); brewed green tea's figure is verified in our brewed green tea guide against USDA FoodData Central (source).
Which one should you pick?
Pick brewed green tea when you want the lighter dose or a slower ramp, and Rockstar Boom 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 Boom: the full caffeine guide
- brewed green tea: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
- Compare any two of 120+ drinks
FAQ
Does Rockstar Boom or brewed green tea have more caffeine? Rockstar Boom: 160mg per 16 oz can versus 28mg per 8 oz cup for brewed green tea.
Which is stronger per ounce? Rockstar Boom, at about 10.0mg per fluid ounce versus 3.5mg for brewed green 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.