Skip to content
BrewnoteAll articles

Coffee Caffeine and Decaf

How much caffeine is actually in a cup, a shot, a pot — and in decaf.

An 8 oz cup of brewed coffee averages about 95 mg of caffeine, a single espresso shot about 63 mg, and a cup of decaf about 2 mg. Those averages hide a wide spread: bean species, grind, dose and brew time all move the number, and two cups from the same café can differ by 50 percent.

These guides give the ranges rather than a single figure, and say where the evidence is genuinely uncertain — decaf's effect on hydration, for instance, is much thinner ground than the confident headlines suggest.

What you'll learn

  • Milligram figures by serving size, brew method and bean species
  • Why decaf is not caffeine-free, and what the 97 percent rule actually means
  • The four industrial decaffeination processes, including Swiss Water and CO₂
  • Where the 400 mg per day guideline comes from and who it does not apply to

6 articles on caffeine & decaf

Common questions about caffeine & decaf

How much caffeine is in a cup of coffee?

About 95 mg in an 8 oz cup of brewed coffee, per USDA figures. A 12 oz mug is closer to 140 mg, and a full 12-cup pot brewed to its marked capacity holds roughly 1,000 mg spread across the carafe.

Does decaf have caffeine?

Yes, a small amount. US regulations require at least 97 percent of caffeine to be removed, which leaves roughly 2 mg in an 8 oz cup against about 95 mg in regular. A decaf espresso shot typically holds 3 to 15 mg.

How much caffeine is too much?

The FDA cites 400 mg a day — about four 8 oz cups — as not generally associated with negative effects for healthy adults. That figure does not apply to pregnancy, to people on certain medications, or to anyone with a diagnosed heart-rhythm condition.

Related topics