Red Bull has more caffeine than Barq's root beer on both counts: 80mg per 8.4 oz can against 22mg per 12 oz can, and about 10mg per fluid ounce against 2. 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.
Red Bull vs Barq's root beer: the numbers
| Red Bull | Barq's root beer | |
|---|---|---|
| Caffeine per serving | 80mg per 8.4 oz can | 22mg per 12 oz can |
| Caffeine per fl oz | 9.5mg | 1.8mg |
| Servings to reach 400mg (FDA context) | 5.0 | 18.2 |
Sources: Red Bull's figure is verified in our Red Bull caffeine guide against Red Bull label / Caffeine Informer (source); Barq's root beer's figure is verified in our Barq's root beer guide against Coca-Cola brand data (source).
The concentration gap is the striking part: Red Bull packs roughly 5 times the caffeine per ounce. Sipping speed matters at that density; a 8.4 oz can finished in minutes hits differently than the same milligrams spread over a slow cup.
Which one should you pick?
Pick Barq's root beer when you want the lighter dose or a slower ramp, and Red Bull 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
- Red Bull: the full caffeine guide
- Barq's root beer: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
FAQ
Does Red Bull or Barq's root beer have more caffeine? Red Bull: 80mg per 8.4 oz can versus 22mg per 12 oz can for Barq's root beer.
Which is stronger per ounce? Red Bull, at about 9.5mg per fluid ounce versus 1.8mg for Barq's root beer.
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.