Vanilla Coke vs Diet Barq's root beer: which has more caffeine?

Vanilla Coke has more caffeine than Diet Barq's root beer: 34mg vs 0mg in the same 12 oz can. That is a 34mg gap, and since the cans match, the per-serving number is the whole story.

Vanilla Coke vs Diet Barq's root beer: the numbers

Sources: Vanilla Coke's figure is verified in our Vanilla Coke caffeine guide against Caffeine Informer (source); Diet Barq's root beer's figure is verified in our Diet Barq's root beer guide against Caffeine Informer / Coca-Cola brand data (source).

The concentration gap is the striking part: Vanilla Coke packs roughly 283 times the caffeine per ounce. Sipping speed matters at that density; a 12 oz can finished in minutes hits differently than the same milligrams spread over a slow cup.

Which one should you pick?

Pick Diet Barq's root beer when you want the lighter dose or a slower ramp, and Vanilla Coke 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

• Vanilla Coke: the full caffeine guide
• Diet Barq's root beer: the full caffeine guide
• The verified caffeine database

FAQ

Does Vanilla Coke or Diet Barq's root beer have more caffeine? Vanilla Coke: 34mg per 12 oz can versus 0mg per 12 oz can for Diet Barq's root beer.

Which is stronger per ounce? Vanilla Coke, at about 2.8mg per fluid ounce versus 0.0mg for Diet Barq's root beer.