Coca-Cola (355 ml)に含まれるカフェイン量はどれくらい？

A 355 ml (12 fl oz) can of Coca-Cola contains 34 mg of caffeine. That works out to 9.6 mg per 100 ml, making it a mild source of caffeine compared to coffee or energy drinks.

For perspective, the same volume of drip coffee delivers about 96 mg of caffeine—roughly 2.8 times as much. A single can of Coca-Cola therefore provides the caffeine equivalent of about 0.4 cups of coffee. Most healthy adults will feel a subtle lift in alertness within 15 to 45 minutes after drinking it, with the effect peaking around one hour and then gradually tapering off. Because the dose is modest, the stimulant sensation is often described as gentle rather than jittery.

At 34 mg, this can represents just 9% of the widely cited 400 mg daily limit for healthy adults set by the FDA and the EFSA. It’s a figure that allows most people to enjoy a Coca-Cola without worrying about exceeding safe caffeine boundaries, provided they keep an eye on other sources throughout the day.

Coca-Cola (355 ml)が体内にどれくらい残るか

Caffeine follows first-order elimination kinetics in the body, with a population-average half-life of 5.7 hours. That means every 5.7 hours, the amount of caffeine still circulating drops by half. Starting from the 34 mg dose in a single can of Coca-Cola, the arithmetic unfolds predictably: after 3 hours, approximately 24 mg remain (34 × 0.5^(3/5.7) ≈ 24 mg); after 6 hours, about 16 mg; after 9 hours, roughly 11 mg; and after 12 hours, the level falls to around 8 mg. These numbers assume an average metabolizer; individual rates can vary by several hours based on genetics, liver function, and whether the person is a smoker or takes oral contraceptives.

If someone drinks a can of Coca-Cola at 15:00 (3 p.m.), the timeline becomes practical. By 18:00, roughly 24 mg remain—still enough for a mild stimulant effect. By 21:00 (6 hours post-consumption), about 16 mg linger, which is less than the caffeine in half a can of cola. By midnight (9 hours), only 11 mg remain, an amount unlikely to disrupt sleep for most people, though sensitive individuals may still notice a slight effect. The interactive caffeine half-life calculator lets you model these decay curves for any starting dose and personal half-life estimate, giving a more tailored picture of when caffeine clears your system.

With 34 mg of caffeine per can, Coca-Cola leaves a wide safety margin under the standard 400 mg daily limit for healthy adults. You could theoretically consume 11 cans (374 mg) and still stay under the cap, though the sugar content—39 grams per can—would far exceed dietary recommendations long before caffeine became the limiting factor. For those monitoring caffeine alone, the math is straightforward: each can uses 9% of the daily allowance, so even four cans (136 mg) consume only about a third of the limit. The safe daily limit by body weight tool can refine this number for your specific weight, as smaller individuals may have a lower personal threshold.

Sleep disruption is a more immediate concern for many. Caffeine’s half-life means that timing matters. If you aim for a 23:00 (11 p.m.) bedtime with minimal caffeine on board—say, less than 10 mg to avoid any effect on sleep architecture—you would need to finish your last Coca-Cola by about 13:00 (1 p.m.), roughly 10 hours earlier. However, because 34 mg is a relatively low dose, a can consumed at 18:00 (6 p.m.) leaves about 18 mg at 23:00, an amount that most people can tolerate without noticeable sleep disturbance. The 2013 study by Drake et al. (Journal of Clinical Sleep Medicine) found that 400 mg of caffeine taken six hours before bed still reduced total sleep time by over an hour, but a dose as small as 34 mg is far below that threshold. Still, individuals with caffeine sensitivity, slow metabolizers, or anxiety disorders may feel residual effects even from this modest amount. The latest cup before bedtime calculator can model exactly when your last cola should be based on your desired wind-down window.

Special populations should apply more conservative limits. The EFSA recommends that pregnant women limit caffeine to 200 mg per day; one can of Coca-Cola uses 17% of that budget, leaving room for other sources if carefully managed. For adolescents, Health Canada suggests a maximum of 2.5 mg per kilogram of body weight per day. A 50 kg (110 lb) teenager would have a 125 mg ceiling, so a single can is well within bounds, but multiple cans combined with other caffeinated products could push them close to the limit. Tracking intake with a tool like CoffeeLog can help ensure these boundaries are respected without guesswork.

Among sodas, Coca-Cola’s 34 mg per 355 ml sits in the lower-middle of the caffeine spectrum. It is noticeably less than Mountain Dew (54 mg) and Dr Pepper (42 mg), and well below the European mate-based soda Club-Mate (66 mg per 330 ml). It edges out Barq’s Root Beer (22 mg) and is nearly identical to Diet Pepsi (35 mg) and Coca-Cola Coke Zero (34 mg). Regular Pepsi contains 38 mg, just 4 mg more, a difference too small to be functionally meaningful for most people. This clustering around the 30–40 mg range makes the classic cola category a relatively consistent, low-dose caffeine option.

When compared with coffee, the gap widens dramatically. A standard 240 ml (8 fl oz) cup of drip coffee delivers 96 mg of caffeine—2.8 times the amount in a 355 ml Coca-Cola, despite being a smaller volume. On a per-milliliter basis, Coca-Cola provides 9.6 mg per 100 ml, whereas drip coffee averages about 40 mg per 100 ml. Even a single 30 ml espresso shot (63 mg) nearly doubles the can’s caffeine. Energy drinks also dwarf the cola: a 250 ml can of Red Bull contains 80 mg, and a 473 ml can of Monster Energy holds 160 mg. In this landscape, Coca-Cola functions as a mild stimulant, more akin to a cup of green tea (28 mg per 240 ml) than to any high-caffeine beverage.

This positioning means that for someone accustomed to coffee, a can of Coca-Cola is unlikely to replace the morning jolt. But for those who are caffeine-sensitive or simply want a small lift without overstimulation, it fits neatly. The side-by-side drink comparison tool lets you stack Coca-Cola against any other drink in our dataset, making it easy to see how it stacks up for your own tolerance and habits.

Coca-Cola (355 ml)の数値を左右する要素

The 34 mg figure applies specifically to the classic Coca-Cola formulation sold in a 355 ml (12 fl oz) can in the United States. However, caffeine content can shift across different sizes, recipes, and serving formats. The most straightforward variation is the smaller 330 ml can common in Europe and other markets, which contains 32 mg of caffeine—slightly less simply because there is less liquid. Our dataset includes a dedicated page for Coca-Cola (330 ml), 32 mg, reflecting that regional difference.

Within the Coca-Cola family, the biggest caffeine jump comes from the diet versions. Coca-Cola Diet Coke packs 46 mg per 355 ml can—35% more than regular Coca-Cola—due to a different flavor and caffeine formulation. Meanwhile, Coca-Cola Coke Zero matches the classic at 34 mg per 355 ml. These differences matter for anyone tracking caffeine intake closely, as switching from regular to Diet Coke nearly doubles the caffeine per can. Fountain-dispensed Coca-Cola may also exhibit minor variation because of syrup-to-water ratios, but the intended target remains the same 34 mg per 12 oz serving.

For those who want the taste without the stimulant, Caffeine-Free Coca-Cola is widely available and contains only trace amounts of caffeine—typically less than 2 mg per serving, far below a pharmacologically active dose. Our guide on Caffeine-Free Coca-Cola の完全な飲料オプション details all the zero- and low-caffeine alternatives. Even regular Coca-Cola’s 34 mg is considered low; a single shot of espresso (30 ml) delivers 63 mg, nearly double the can’s content in a fraction of the volume.

Batch-to-batch variation in commercial soda production is minimal because caffeine is added as a precisely measured ingredient. The 34 mg figure is the manufacturer’s declared value and is consistent with independent lab analyses compiled by the USDA FoodData Central. We treat it as a reliable estimate, but we acknowledge that any single can might differ by a milligram or two due to normal manufacturing tolerances. When published values disagree—some older sources list 35 mg or 32 mg—it usually reflects a different serving size or an outdated formulation. We monitor official product data and update our figure if a recipe change occurs.

この数値の出典

The 34 mg caffeine value for a 355 ml can of Coca-Cola is drawn from the manufacturer’s published nutritional information and is cross-verified against the USDA FoodData Central database, which aggregates laboratory analyses of commercially available products. The Coca-Cola Company has consistently reported this figure for the classic formulation in the United States, and independent testing generally confirms it within a narrow margin of error. When you encounter slightly different numbers—such as 32 mg for a 330 ml can or 35 mg in some older references—the discrepancy almost always traces back to serving size, regional recipe variations, or outdated data. We rely on the most current, serving-size-specific values available.

Transparency is central to how we maintain this page. Our entire dataset is open and version-controlled; you can inspect the raw numbers and the provenance notes at the open caffeine dataset behind these pages. If a manufacturer reformulates a drink or new authoritative lab data emerges, we update the figure and note the change. We also periodically review the peer-reviewed literature and regulatory guidance—such as the EFSA’s 2015 safety assessment and the FDA’s consumer updates—to ensure our contextual framing remains accurate. This page is not static; it reflects the best available evidence at the time of writing. If you spot a value that seems off, the dataset’s open structure allows anyone to submit a correction with a verifiable source.

結論

A 355 ml (12 fl oz) can of Coca-Cola contains 34 mg of caffeine, which is 9.6 mg per 100 ml. This is a mild dose—equivalent to about 0.4 cups of drip coffee (96 mg per 240 ml) and just 9% of the FDA and EFSA daily limit of 400 mg for healthy adults. After drinking, caffeine levels decay with a half-life of roughly 5.7 hours: 24 mg remain at 3 hours, 16 mg at 6 hours, 11 mg at 9 hours, and 8 mg at 12 hours. For most people, a single can poses little risk of sleep disruption or overstimulation, but multiple cans add up quickly. Those who need to avoid caffeine entirely can opt for Caffeine-Free Coca-Cola, which contains only trace amounts. Use the tools on this site to model your personal caffeine clearance and daily budget.