How Much Caffeine Is in a Cup of Coffee, and How Much Is Too Much?
Coffee is one of the main sources of caffeine. Even "one cup" varies widely in caffeine with beans and brewing, so knowing what sets the amount helps you estimate your intake. This article is general information; for decisions about your own health, talk to a medical professional.
1. What sets the caffeine in a cup
- Bean species: robusta has roughly twice the caffeine of arabica.
- Dose: caffeine dissolves readily and mostly comes out early in the brew, so for the same beans, the amount of coffee used matters most.
- Cup size and recipe: espresso is concentrated but small; a large mug of drip coffee can be weaker yet contain more in total. Fully steeped cold brew reaches caffeine levels similar to hot coffee (Fuller & Rao, 2017).
- Roast level: caffeine barely breaks down during roasting, so the factors above make far bigger differences.
EFSA (2015) gave rough examples of about 90 mg in a cup of filter coffee (about 200 mL) and about 80 mg in an espresso. Actual amounts vary much more than this by café and recipe.
2. How much per day
| Group | EFSA (2015) | Korea MFDS |
|---|---|---|
| Healthy adults | Up to 400 mg/day, single doses up to 200 mg, raise no safety concerns | 400 mg/day or less |
| Pregnant and breastfeeding | Up to 200 mg/day | Pregnant women 300 mg/day or less |
| Children and adolescents | Up to 3 mg per kg body weight per day | 2.5 mg per kg body weight per day or less |
Agencies differ somewhat in their evidence and thresholds. During pregnancy it is safer to follow the lower figure. Caffeine is also in tea, chocolate, cola, energy drinks and some medicines, so think in terms of the daily total.
3. Why people react differently
How fast the body clears caffeine varies widely with genetics, smoking, pregnancy and some medications. The same amount keeps one person awake and barely affects another. If caffeine in the late afternoon disturbs your sleep, moving your coffee earlier can help.
Putting it into practice
- To cut back: use less coffee, choose 100% arabica, or swap one cup a day for decaf — the most effective options.
- When buying coffee: large drinks often contain two or three shots; asking how many shots gives a rough idea of the amount.
- Worried about sleep? Try moving your last coffee to at least six hours before bed.
References
- EFSA Panel on Dietetic Products, Nutrition and Allergies (2015). Scientific Opinion on the safety of caffeine. EFSA Journal, 13(5), 4102.
- Korea Ministry of Food and Drug Safety. Recommended maximum daily caffeine intake (adults 400 mg, pregnant women 300 mg, children and adolescents 2.5 mg/kg body weight).
- Fuller, M. & Rao, N. Z. (2017). The effect of time, roasting temperature, and grind size on caffeine and chlorogenic acid concentrations in cold brew coffee. Scientific Reports, 7, 17979.