How Much Caffeine Is in a Cup of Coffee?
It depends on the bean, the dose and the brew - not much on the roast. Here's a practical breakdown of caffeine per cup, with numbers.
There's no single number - it depends on three things: the bean, the dose, and the brew. Roast level barely matters.
The Three Levers
- Bean. Robusta has about 2,400 mg of caffeine per 100 g of grounds; Arabica about 1,300 mg - close to double.
- Dose. How many grams of coffee you use. This is the biggest everyday variable. A weak 12 g cup and a strong 30 g cup differ hugely.
- Brew. Longer contact and less dilution extract more. A concentrated decoction or espresso pulls more per gram than a fast, watery drip.
Roast: dark roast has marginally less caffeine by weight than light - a difference too small to notice.
Rough Numbers (per cup)
Assuming a strong 30 g dose of grounds:
100% Arabica
Caffeine: ~390 mg per 30 g cup100% Arabica
70% Arabica / 30% Robusta (classic filter blend)
Caffeine: ~490 mg per 30 g cup70% Arabica / 30% Robusta
100% Robusta
Caffeine: ~720 mg per 30 g cup0% Arabica / 100% Robusta
A typical home cup uses 12-18 g, not 30, so real-world cups often land around 90-160 mg. Espresso is ~60-100 mg per shot - less total than a big filter coffee, just more concentrated.
How Much Is Too Much?
About 400 mg a day is the commonly cited safe ceiling for healthy adults - roughly 3-4 strong cups. Pregnancy guidance is ~200 mg. Past your limit you get jitters, a racing heart and poor sleep, not more energy.
Want More (or Less)?
- More: raise the Robusta share, use more grounds, brew a concentrate.
- Less: more Arabica, smaller dose, or a chicory filter blend (chicory has no caffeine).
Filter Coffee (70% Arabica, 30% Robusta)
Filter Coffee (70% Arabica, 30% Chicory)
Related Reading
Arabica vs Robusta: Caffeine Compared, Highest Caffeine Coffee in India, and Best Coffee for Caffeine.
Caffeine per cup is set by the bean and the dose, not the roast. A strong Robusta-heavy cup can be 3x a weak Arabica one.