E34Going deeper
Caffeine — How Much Is Enough
How much caffeine is in a cup depends on the bean, brew and cup size. A general reference for healthy adults per EFSA/FDA, and who should be careful.
Coffee wakes you up thanks to caffeine, a mild stimulant found naturally in coffee beans. For most healthy adults, a few cups a day is perfectly normal. But how many is "a few", and how much caffeine is really in a cup? This article offers general reference points, not personal medical advice.
How much caffeine is in your cup?
There is no fixed number for "one cup of coffee". The amount depends on several factors:
| Factor | Effect |
|---|---|
| Coffee variety | Robusta usually contains more caffeine than Arabica, about twice as much by commonly cited industry figures |
| Amount of grounds | More coffee per amount of water means a stronger cup with more caffeine |
| Brew method and contact time | Longer brewing, hot water and finer grounds usually extract more |
| Cup size | A large cup naturally holds more than a small one |
So a small, strong phin coffee and a large iced milk coffee can contain very different amounts of caffeine, even though both are "one cup". For an exact figure you need data for the specific product and brew.
A common misconception is that dark roast is "stronger". Bold, bitter flavour comes from roasting, but caffeine is hardly destroyed by it. Roast level is therefore not the main factor in caffeine content.
A reference level for healthy adults
Food safety bodies such as EFSA (Europe) and the FDA (United States) both give a reference level: healthy adults can consume up to about 400 mg of caffeine a day without safety concerns. For medium cups of brewed coffee, that equals a few cups, depending on strength.
Remember that caffeine is not only in coffee. Tea, fizzy drinks, energy drinks, cocoa and chocolate contain it too. When you add up your day, count these as well.
Who should be careful?
The 400 mg level applies to healthy adults in general. These groups should limit intake and ask a doctor what is right for them:
- Children and teenagers;
- Pregnant and breastfeeding women, since health authorities usually give a lower level for this group;
- People sensitive to caffeine, or with heart rhythm, blood pressure, sleep or anxiety concerns;
- People taking medication that may interact with caffeine.
Everyone reacts differently. After the same cup, one person feels pleasantly alert while another feels jittery, with a racing heart or an upset stomach.
Signs you may be having too much
Your body often tells you when caffeine goes beyond your comfort zone:
- Jitters, shaky hands, a racing heart;
- Trouble falling asleep or sleeping lightly;
- Restlessness, irritability, stomach pain or heartburn;
- Needing more and more coffee to feel awake.
If you notice these, cut back a cup, choose a smaller size or brew it lighter. If symptoms persist, see a doctor.
Drinking sensibly
A few simple habits make coffee more comfortable:
- Avoid coffee close to bedtime. Caffeine can remain in the body for hours, so many people stop in the early afternoon. Find the time that suits your sleep.
- Sip slowly and avoid an empty stomach if you are prone to stomach upset.
- Alternate with plain water through the day.
- Count large iced milk coffees and takeaway cups — they are often bigger than you think.
If you love the flavour but want less caffeine, brew a smaller cup or drink earlier in the day.
Know the bean, choose the right cup
Knowing that Robusta usually has more caffeine than Arabica helps you pick a cup that suits your body and habits. To see how the two differ in flavour, read The main coffee varieties. And to brew in the right ratio, see Brewing basics.
Frequently asked questions
Does dark roast have more caffeine than light roast?
Not necessarily. Roasting destroys little caffeine, so the difference between roast levels is small. What mainly decides the caffeine in your cup is the coffee variety, the amount of grounds and the brew method.
When is a sensible time to drink coffee?
Caffeine can stay in the body for many hours, so many people skip coffee in the late afternoon and evening. Watch your own sleep to find the cut-off that suits you.
I feel jittery and sleep badly after coffee. What should I do?
That suggests you are sensitive to caffeine. You can cut back, drink earlier in the day, and see a doctor if symptoms persist.
