Starbucks cold brew (grande) has more caffeine than Rockstar Original: 205mg vs 160mg in the same 16 oz grande. That is a 45mg gap, and since the cans match, the per-serving number is the whole story.
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 Starbucks cold brew (grande): the numbers
| Rockstar Original | Starbucks cold brew (grande) | |
|---|---|---|
| Caffeine per serving | 160mg per 16 oz can | 205mg per 16 oz grande |
| Caffeine per fl oz | 10.0mg | 12.8mg |
| Servings to reach 400mg (FDA context) | 2.5 | 2.0 |
Sources: Rockstar Original's figure is verified in our Rockstar Original caffeine guide against Rockstar product page (source); Starbucks cold brew (grande)'s figure is verified in our Starbucks cold brew (grande) guide against Starbucks menu data (source).
Which one should you pick?
Pick Rockstar Original when you want the lighter dose or a slower ramp, and Starbucks cold brew (grande) 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
- Starbucks cold brew (grande): the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
FAQ
Does Rockstar Original or Starbucks cold brew (grande) have more caffeine? Starbucks cold brew (grande): 205mg per 16 oz grande versus 160mg per 16 oz can for Rockstar Original.
Which is stronger per ounce? Starbucks cold brew (grande), at about 12.8mg per fluid ounce versus 10.0mg for Rockstar Original.
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.