Coca-Cola
How much caffeine is in Barq's Root Beer?
Sources checked claim by claim by an AI review. Approved for publishing by Oleksii Y. on 2026-10-09.
One 12 fl oz can of Barq's Root Beer has 22 mg of caffeine, according to The Coca-Cola Company (coca-cola.com, US).
How Barq's Root Beer compares
- Strength: 6.2 mg per 100 ml.
- One 12 fl oz can has as much caffeine as about a quarter to a third of a cup of brewed coffee, which has 94.8 mg per 8 fl oz cup.
- Of the 30 other sodas in our soda chart, 17 have more caffeine per serving and 13 have less.
How much will be left at bedtime?
1 × 12 fl oz can of Barq's Root Beer
Left at 11:00 PM (8 h later), average metabolism
≈ 7 mg
Range 3–11 mg (fast to slow metabolism)
22 mg is already at or under the 50 mg this tool aims to have left at bedtime.
What sleep studies found near this dose
- Gardiner et al. 2025 (randomized trial): In 23 healthy young men, 100 mg taken 12, 8 or 4 hours before bed had no significant effect on measured or self-rated sleep.
- Gardiner et al. 2023 (meta-analysis): To avoid losing sleep time, the authors suggest a coffee (107 mg per 250 ml) at least 8.8 hours before bed.
Estimate from a simple model: half-life of 3, 5 or 8 hours, 50 mg bedtime target. How we calculate
Caffeine by size
| Serving | Caffeine |
|---|---|
| 12 fl oz can | 22 mg |
| 12 fl oz Barq's Zero Sugar Root Beer | 0 mg |
How long does Barq's Root Beer stay in your system?
Our model halves caffeine every 5 hours for average metabolism, and every 3 or 8 hours for fast or slow metabolism. From one 12 fl oz can of Barq's Root Beer (22 mg), about 11 mg is still in your body 5 hours later and about 6 mg after 10 hours. If you clear caffeine slowly (an 8-hour half-life), about 9 mg is left after 10 hours.
Estimated caffeine left at 11:00 PM from one 12 fl oz can (22 mg), using a half-life of 5 hours for average metabolism and 3 to 8 hours for the range. How we calculate
| Had at | Left at bedtime (average) | Range |
|---|---|---|
| 8:00 AM (15 h before bed) | ≈ 3 mg | 1–6 mg |
| 12:00 PM (11 h before bed) | ≈ 5 mg | 2–8 mg |
| 3:00 PM (8 h before bed) | ≈ 7 mg | 3–11 mg |
| 6:00 PM (5 h before bed) | ≈ 11 mg | 7–14 mg |
How many fit in a day?
Reference amounts are for caffeine from all sources combined. Counted at the upper end of the stated amount, one serving at a time:
- Up to 400 mg a day for most healthy adults (FDA, EFSA): about 18 servings.
- Up to 200 mg at one time for healthy adults (EFSA): about 9 servings in one go.
- Up to 200 mg a day in pregnancy (EFSA, NHS): about 9 servings.
These are reference amounts for groups of people, not a personal limit. Some people feel jittery or sleep worse on much less. See the cutoff calculator for timing.
Good to know
Most root beers have no caffeine: CSPI says Barq's has 22 mg, but most brands are caffeine-free.
Barq's Root Beer vs other root beer and ginger ale drinks
- Root beer: Barq's Root Beer has more caffeine than root beer per 100 ml (6.2 vs 0 mg). Barq's Root Beer: 22 mg per 12 fl oz can; Root beer: 0 mg per 8 fl oz (237 ml), most brands.
- A&W Root Beer: Barq's Root Beer has more caffeine than A&W Root Beer per 12 fl oz can: 22 mg vs 0 mg.
- Canada Dry Ginger Ale: Barq's Root Beer has more caffeine than Canada Dry Ginger Ale per 12 fl oz can: 22 mg vs 0 mg.
- Ginger ale: Barq's Root Beer has more caffeine than ginger ale per 12 fl oz can: 22 mg vs 0 mg.
Common questions
How much caffeine is in Barq's Root Beer?
The Coca-Cola Company (coca-cola.com, US) gives 22 mg of caffeine per 12 fl oz can. Other sizes are in the table on this page.
How many Barq's Root Beer servings can I have in a day?
The FDA and EFSA cite up to 400 mg of caffeine a day, from all sources combined, for most healthy adults. At 22 mg per 12 fl oz can, that is about 18 servings if Barq's Root Beer is your only source. In pregnancy the reference is 200 mg a day.
How late can I drink Barq's Root Beer?
One serving has about 22 mg, which is at or under the 50 mg our calculator aims to have left at bedtime, so it sets no cutoff for a single serving. Several servings add up.
Does Barq's Root Beer have more caffeine than Root beer?
Barq's Root Beer has more caffeine than root beer per 100 ml (6.2 vs 0 mg). Barq's Root Beer: 22 mg per 12 fl oz can; Root beer: 0 mg per 8 fl oz (237 ml), most brands.
How long does Barq's Root Beer stay in your system?
Of the 22 mg in one 12 fl oz can, roughly 11 mg remains after 5 hours and 6 mg after 10 hours with our average 5-hour half-life. From fast to slow metabolism, 10 hours later it is between 2 and 9 mg.
Where the number comes from
- Barq's. The Coca-Cola Company (coca-cola.com, US). Root Beer nutrition facts: "CAFFEINE CONTENT: 22 mg/12 fl oz"; Zero Sugar Root Beer text: "is caffeine free" Accessed 2026-10-09. Source ↗
- Caffeine chart. Center for Science in the Public Interest. table "Soft drinks", row "Barq's Root Beer | 12 oz. | 22" Accessed 2026-10-09. Source ↗
- How much caffeine is in coffee, tea, soda, and other foods? Center for Science in the Public Interest. Section "How much caffeine is in soda?": "Root beer: Barq's has 22 mg, but most brands are caffeine-free" Accessed 2026-10-09. Source ↗
Recipes and labels change. If a number here no longer matches the label, the label wins.
General information, not medical advice
If you feel unwell after caffeine — for example chest pain, a fast or irregular heartbeat that does not settle, fainting, confusion or trouble breathing — get urgent medical help. If you are pregnant or breastfeeding, under 18, take medication, or have a heart, liver or anxiety condition, high blood pressure or a sleep disorder, ask a doctor or pharmacist what amount is right for you.
Sources
- U.S. Food and Drug Administration (2024). Spilling the Beans: How Much Caffeine is Too Much? FDA Consumer Updates. fda.gov ↗
- European Food Safety Authority. Caffeine | EFSA. EFSA topic page (summary of the 2015 Scientific Opinion on the safety of caffeine). efsa.europa.eu ↗
- NHS. Foods to avoid in pregnancy. NHS. nhs.uk ↗
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