Caffeine in Popular Sodas: A&W, Barq's, and More

A&W root beer is not listed in the dataset here; a reasonable estimate is 0–22 mg (estimate) of caffeine per can depending on the variety (many root beers are caffeine-free while Barq's contains 22 mg per 355 ml).

• Barq's Root Beer (355 ml) contains 22 mg of caffeine — a low dose compared with colas and energy drinks.
• Coca-Cola (355 ml) has 34 mg46 mg54 mg.
• Energy drinks and cold-brew coffee can be 4–10× higher: Red Bull 250 ml = 80 mg, Monster 473 ml = 160 mg, cold brew 240 ml = 200 mg.
• FDA recommends a max of 400 mg/day for healthy adults; pregnancy guidance ~200 mg/day; American Academy of Pediatrics discourages routine caffeine for adolescents.

Root beer caffeine: Barq's vs A&W

Barq's Root Beer is listed in the dataset at 355 ml = 22 mg (6.2 mg/100 ml). A&W root beer is not in this dataset, so we cannot state an exact number from these data. Many commercial root beers are produced both as caffeine-free and caffeinated varieties; where caffeine isn’t listed you should assume 0 mg unless the label or manufacturer says otherwise. Use USDA FoodData Central or the product label for definitive values.

How caffeinated are common sodas (quick comparison)

This table lists popular sodas and similar soft drinks from the dataset so you can compare at a glance.

How soda caffeine compares with coffee and energy drinks

Sodas are low-to-moderate sources of caffeine compared with coffee and many energy drinks. For context from the same dataset: a standard drip coffee (240 ml) = 96 mg, cold brew (240 ml) = 200 mg, and a Starbucks Grande Pike Place (473 ml) = 310 mg. Energy drinks like Monster (473 ml) at 160 mg or Bang (473 ml) at 300 mg deliver far more caffeine than a can of cola or root beer.

What determines caffeine in a soda

Key variables are formulation and serving size. Cola-style sodas usually contain added caffeine as an ingredient; root beers are often made without added caffeine. Citrus sodas and many orange sodas (e.g., Sunkist) often include added caffeine at levels similar to cola. Manufacturer recipe changes, regional formulations, and serving volume (ml) explain most variation. For verified amounts, consult product labels and USDA FoodData Central entries; regulatory bodies like the FDA monitor labeling standards.

Health, safety, and timing

Regulatory and clinical guidance is a helpful guardrail: the FDA cites about 400 mg/day as a safe upper limit for most healthy adults; many authorities (and some studies cited by EFSA) recommend less during pregnancy—commonly ≈200 mg/day. The American Academy of Pediatrics advises limiting caffeine in adolescents.

Caffeine metabolism is population‑average: half-life ≈ 5.7 hours. In other words, caffeine from a drink declines exponentially; after ~3 h about 69% remains, after 6 h about 48%, after 9 h about 33%, after 12 h about 23%. This matters for night-time intake and sleep.

Practical tips and tracking

To manage intake: read product labels, favor caffeine-free versions if you need zero caffeine, and note serving sizes. If you need to total daily intake (and include coffee, tea, and energy drinks), track every drink — apps like CoffeeLog make logging straightforward and can add values from manufacturer data automatically. If you are pregnant, have cardiovascular issues, anxiety, or are giving advice for children, consult a healthcare professional; information here is educational, not medical advice.

Bottom line

Barq's root beer provides 22 mg per 355 ml; many other root beers (including some A&W varieties) are caffeine-free, which is why an A&W value is estimated here as 0–22 mg (estimate). For absolute certainty check the label or USDA FoodData Central and use a tracker like CoffeeLog to sum caffeine across drinks and time.

Sources and guidance referenced in this article include USDA FoodData Central, the U.S. Food and Drug Administration (FDA), European Food Safety Authority (EFSA) summaries, the Mayo Clinic, and the American Academy of Pediatrics.

How much caffeine from a single 355 ml Barq's can remains after 6 hours?

After 6 hours a 355 ml can of Barq's (22 mg) will have about 11 mg of caffeine remaining in the body using the population-average elimination model. Using the first-order elimination formula: remaining = 22 × 0.5^(6 / 5.7) = 22 × 0.5^(1.0526) ≈ 22 × 0.483 ≈ 10.6 mg, which rounds to 11 mg.

First-order elimination is exponential decay where the dose halves every half-life. The dataset lists Barq's Root Beer at 22 mg per 355 ml and the decay model uses a population-average half-life of 5.7 hours (dataset model). For a quick, interactive calculation for any drink and timing see the caffeine half-life calculator.

How many 355 ml cans of Coca-Cola would equal the FDA's 400 mg/day guidance?

You would reach the U.S. Food and Drug Administration's 400 mg/day guidance with about twelve 355 ml cans of Coca-Cola because each 355 ml Coca-Cola contains 34 mg. Arithmetic: 400 mg ÷ 34 mg per can = 11.76 cans, so you would need 12 cans to meet or exceed 400 mg.

The FDA daily limit is 400 mg/day for most healthy adults, according to the U.S. Food and Drug Administration. The dataset lists Coca-Cola (355 ml) = 34 mg; for body-weight adjusted guidance visit our safe daily limit by body weight tool and our safe caffeine intake guide.

If I mix a soda, a coffee, and an energy drink in one day, how quickly does that sum toward the limit?

Mixing a 355 ml Mountain Dew (54 mg), a 240 ml drip coffee (96 mg), and a 250 ml Red Bull (80 mg) produces a straight sum of 230 mg of caffeine toward your daily total. Arithmetic: 54 + 96 + 80 = 230 mg, which is 57.5% of the FDA 400 mg/day guidance (the FDA puts the guidance at 400 mg/day).

A cumulative total is the arithmetic sum of milligrams from every source. The dataset values used here are Mountain Dew = 54 mg (355 ml), drip coffee = 96 mg (240 ml), and Red Bull (250 ml) = 80 mg; if you want to compare many drinks side-by-side use our caffeine half-life calculator or the side-by-side drink comparison tool to track totals across the day.

Can a caffeinated soda you drink within six hours of bedtime still reduce sleep?

Yes — caffeine from a soda consumed within six hours of bedtime can affect sleep; controlled research shows high doses reduce sleep even when taken six hours before bed. Drake et al. (2013) found that 400 mg of caffeine consumed 6 hours before bedtime cut objective sleep time by more than an hour in a laboratory study (Drake et al., 2013).

A sleep intervention study is research that measures sleep outcomes after controlled caffeine dosing. To see how much remains at bedtime from a typical soda: if you drink a 355 ml Mountain Dew (54 mg) six hours before bed the residual is 54 × 0.5^(6 / 5.7) = 54 × 0.483 ≈ 26 mg at bedtime; while 26 mg is much smaller than 400 mg, individual sensitivity varies and small residuals can matter in people who are sleep-sensitive. Our latest cup before bed tool uses the same decay math to suggest a cutoff time for your bedtime.

How quickly do multiple small sodas add up across a workday, accounting for elimination?

Caffeine intake adds linearly in milligrams, but elimination reduces earlier doses over time; three small sodas across an 8-hour shift can total roughly 100–200 mg, and residuals from the first two drinks remain when the last one is consumed. Example (dataset values): morning Coca-Cola (34 mg at 9:00), lunch iced tea (45 mg at 13:00), mid-afternoon Red Bull (80 mg at 15:00) gives a raw intake of 34 + 45 + 80 = 159 mg.

Linear addition is summing mg from every source to get a daily intake total. To account for elimination at 17:00 (end of shift): the 9:00 Coca-Cola residual after 8 hours = 34 × 0.5^(8 / 5.7) = 34 × 0.5^(1.4035) ≈ 34 × 0.375 ≈ 12.8 mg; the 13:00 iced tea residual after 4 hours = 45 × 0.5^(4 / 5.7) = 45 × 0.5^(0.7018) ≈ 45 × 0.615 ≈ 27.7 mg; the 15:00 Red Bull residual after 2 hours = 80 × 0.5^(2 / 5.7) = 80 × 0.5^(0.3509) ≈ 80 × 0.78 ≈ 62.4 mg. Summing the residuals at 17:00 gives ≈12.8 + 27.7 + 62.4 = 102.9 mg still active in the body at shift end even though raw intake was 159 mg. For hands-on tracking of overlap and totals use the half-life calculator and compare drinks on our caffeine comparison page.

Bottom line

Barq's Root Beer is 22 mg per 355 ml according to the dataset; A&W root beer is commonly produced both caffeinated and caffeine-free so an A&W value is reasonably estimated as 0–22 mg per can depending on the variety, and for exact labels consult the product packaging or USDA FoodData Central. For daily safety benchmarks, the U.S. Food and Drug Administration puts a general guidance at 400 mg/day for most healthy adults and the European Food Safety Authority (EFSA) notes 200 mg/day for pregnancy considerations (FDA, EFSA 2015).

Caffeine clears by first-order elimination with a population-average half-life of 5.7 hours (dataset model), so a 22 mg Barq's can becomes about 15 mg after 3 hours (22 × 0.5^(3 / 5.7) ≈ 15 mg), about 11 mg after 6 hours (≈10.6 mg), about 7 mg after 9 hours (≈7.3 mg), and about 5 mg after 12 hours (≈5.1 mg). If you need to total intake across sodas, coffee, and energy drinks use our caffeine half-life calculator, check cumulative numbers on the side-by-side comparison, and consult our caffeine-free soda options if you want zero caffeine.