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How Much Caffeine Is In What You're Drinking, and What Counts as Too Much

A cup of coffee isn't a fixed amount of caffeine, and neither is a can of energy drink. Here's roughly what you're actually consuming, and where the commonly cited daily limits come from.

Brewed coffee: roughly 80-100 mg per 8 oz cup

An average 8 oz (240 mL) cup of drip coffee contains somewhere around 95 mg of caffeine, but the real number swings widely based on bean type, roast, and brew strength, so treat this as a ballpark, not a fixed value.

Espresso: roughly 60-65 mg per shot

A single 1 oz espresso shot has less total caffeine than a full mug of drip coffee simply because of its smaller serving size, even though it tastes far more intense per sip.

Tea and energy drinks vary even more widely

Black tea runs roughly 40-50 mg per 8 oz cup, green tea somewhat less, and energy drinks typically range from about 50 mg to well over 150 mg per can depending entirely on the brand and size.

Up to about 400 mg/day is the commonly cited healthy-adult ceiling

Health authorities including the US FDA and the European Food Safety Authority (EFSA) commonly cite roughly 400 mg per day, about four 8 oz cups of coffee, as a level not generally associated with adverse effects in healthy, non-pregnant adults.

Pregnancy guidance is meaningfully lower, around 200 mg/day

Because caffeine crosses the placenta and is cleared more slowly during pregnancy, commonly cited guidance suggests capping intake at roughly 200 mg per day, about half the general adult reference figure.

Why "one cup of coffee" is a moving target

The same drink name can mean very different caffeine amounts depending on brew method, bean origin, roast level, and cup size, which is why any caffeine figure attached to a generic drink name is necessarily an estimate rather than an exact reading. Checking a specific brand's posted caffeine content is more accurate than relying on category averages when precision matters.

Where these limits actually come from

Neither Japan nor China currently sets its own official national daily caffeine limit for adults, so guidance in both markets, and internationally, tends to reference the same handful of Western regulatory figures, chiefly the US FDA's roughly 400 mg reference and EFSA's scientific opinion on caffeine safety, rather than an independently derived local standard.

Frequently Asked Questions

Does an energy drink always have more caffeine than coffee?

Not necessarily. Many popular energy drink cans fall in a similar or even lower caffeine range than a large brewed coffee; the difference in effect people notice often comes from added sugar, taurine, or simply drinking it faster than a hot coffee.

Is decaf coffee actually caffeine-free?

No. Decaffeination typically removes most, but not all, of the caffeine, leaving roughly 2-5 mg per cup rather than zero. That's generally trivial compared to regular coffee, but it isn't literally zero.