Coffee Ratio LabCaffeine Calculator: How Much Caffeine Have You Had Today?
A 240 ml cup of brewed coffee has roughly 95 mg of caffeine and a single espresso about 63 mg, though real amounts vary widely. Health authorities such as the US FDA cite up to 400 mg a day as an amount not generally associated with negative effects for most healthy adults.
Estimates only. Caffeine varies with beans, roast, brewing method and serving size. Lower limits apply during pregnancy (often cited as 200 mg/day), and for children, teens and people with certain health conditions or medications — ask a doctor or pharmacist for advice that fits you.
Caffeine in common drinks (typical estimates)
| Drink | Serving | Approx. caffeine |
|---|---|---|
| Espresso | 30 ml single | ~63 mg |
| Brewed coffee | 240 ml | ~80–100 mg |
| Cold brew (ready to drink) | 240 ml | ~100–200 mg, varies a lot |
| Instant coffee | 240 ml | ~60–80 mg |
| Decaf coffee | 240 ml | ~2–5 mg |
| Black tea | 240 ml | ~40–50 mg |
| Green tea | 240 ml | ~25–30 mg |
Why caffeine amounts vary so much
Robusta beans contain roughly twice as much caffeine as Arabica. Brewing ratio, contact time and serving size matter even more: a large mug of strong French press can contain more caffeine than a double espresso. Cold brew concentrate is especially variable because it uses a lot of coffee. Treat every number here as an estimate rather than a measurement.
How much caffeine is too much?
The US Food and Drug Administration and the European Food Safety Authority both cite about 400 mg per day as an amount not generally associated with harmful effects for healthy adults. Sensitivity varies, and lower amounts are usually advised during pregnancy. If caffeine affects your sleep, heart rate or anxiety, cut back — and ask a healthcare professional about your own situation.
Frequently asked questions
How much caffeine is in a cup of coffee?
A typical 240 ml cup of brewed coffee contains around 95 mg, but anything from about 70 to 140 mg is common.
Does espresso have more caffeine than coffee?
Per milliliter, yes. Per serving, a single espresso (~63 mg) usually has less than a mug of drip coffee.
Does dark roast have more caffeine?
Not meaningfully. By weight, light and dark roasts are similar; by scoop, dark roast can have slightly less because the beans are less dense.
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