How much caffeine is in a cup of coffee?
Roughly 60 to 100 mg in a single espresso shot, and about 95 to 200 mg in a mug of filter coffee, depending on dose, beans, and cup size. Robusta carries roughly double the caffeine of arabica.
There is no single number, because “a cup” can mean a 30 ml espresso or a 350 ml mug, and beans vary. But here are the dependable ranges most sources agree on.
Typical caffeine by drink
- Single espresso shot (about 30 ml): roughly 60 to 100 mg. A double, which is what most cafes actually serve, is roughly 120 to 200 mg.
- Mug of filter or drip coffee (240 to 350 ml): roughly 95 to 200 mg.
- Instant coffee (one teaspoon): roughly 30 to 90 mg.
- Decaf: not zero, usually 2 to 15 mg per cup. See decaf.
A common surprise: per sip, espresso is intense, but a full mug of filter coffee usually delivers more total caffeine than one shot, simply because there is far more liquid and more coffee was brewed. That is the heart of the espresso vs drip question.
What actually moves the number
- How much coffee you used. More grounds means more caffeine, full stop. This is the single biggest factor, bigger than brew method.
- The species of bean. robusta has roughly double the caffeine of arabica by weight. Most specialty coffee is arabica; cheaper blends and many espresso blends include robusta. The contrast is covered in arabica-vs-robusta.
- Cup size. Obvious, but it is why a “cup” is such a slippery unit.
Roast level barely matters, despite the myths, light and dark roast land within a hair of each other once you account for how you measure them.
A rough daily guide
Health authorities generally consider up to about 400 mg of caffeine a day safe for most healthy adults, which is roughly three to four mugs of filter coffee. Pregnant people and those sensitive to caffeine should aim lower. For the full picture of where caffeine comes from and how it behaves, see caffeine-101 and the term caffeine.