Sourced caffeine figures for Barq's Root Beer: every serving size, mg per 100 ml, the coffee comparison, and when to stop before bed.
TL;DR
Barq's Root Beer contains 22 mg of caffeine per 12 oz can (355 ml / 12 oz). That is about 23% of the caffeine in a typical 8 oz cup of brewed coffee (about 95 mg). Concentration: 6.2 mg per 100 ml.
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Barq's Root Beer Caffeine Content by Serving
Figures are for Barq's Root Beer (Coca-Cola).
Serving
Volume
Caffeine
Per 100 ml
Level
12 oz can
355 ml / 12 oz
22 mg
6.2 mg
Low
Source: caffeine figures from Caffeine Informer, accessed 2026-06-11. Values can vary by batch, location, and preparation; check the label or the source for the latest figures.
How Barq's Root Beer Compares to Coffee
At 22 mg per 12 oz can, Barq's Root Beer delivers about 23% of the caffeine in a typical 8 oz cup of brewed coffee (about 95 mg). For a wider comparison across drinks, try the caffeine comparison tool or browse the full caffeine database.
When to Stop Drinking Barq's Root Beer Before Bed
A 12 oz can of Barq's Root Beer (22 mg) stays under the 50 mg sleep-ready threshold from the first sip, so a normal serving is unlikely to delay sleep on its own. Multiple servings stack, though: caffeine's median half-life is about 5 hours, so a second or third serving in the afternoon can still add up past 50 mg by bedtime.
A 12 oz can of Barq's Root Beer contains 22 mg of caffeine, per Caffeine Informer (accessed 2026-06-11). That is about 23% of the caffeine in a typical 8 oz cup of brewed coffee (about 95 mg).
No. Per Caffeine Informer, the sugar-free or diet variant of Barq's Root Beer does not match the regular version's 22 mg. Check the label of the specific variant you are drinking before counting it in your daily total.
Caffeine's median half-life is about 5 hours, so the 22 mg in a 12 oz can drops to roughly 11 mg after 5 hours and 6 mg after 10 hours. Individual half-lives range from about 2 to 12 hours depending on CYP1A2 genetics, medications, smoking, and pregnancy. Model your own curve with the caffeine half-life calculator.
A 12 oz can of Barq's Root Beer stays under 50 mg, so one serving is unlikely to delay sleep at any reasonable hour. If you have several servings, or combine it with coffee or energy drinks, use the Barq's Root Beer sleep cutoff page and the half-life calculator to check your evening total.
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Medical Disclaimer: Caffeine values are approximate figures from the cited public sources. Actual content may vary by batch, location, and preparation, and caffeine metabolism varies widely between individuals. This page is for informational purposes only and is not medical advice. The FDA guideline for healthy adults is up to 400 mg of caffeine per day; the recommended limit during pregnancy is 200 mg per day. Consult a healthcare professional for personalized guidance.