Habits & desk health
Daily caffeine intake calculator
Count today's drinks and your weight to see your total caffeine in milligrams and how it compares with common adult guidelines.
Caffeine varies a lot by brand and brew strength; the figures are typical values per standard serving.
How total caffeine is worked out
Each drink is multiplied by a typical caffeine content per serving and the results are added. The calculator uses 95 mg for a 240 ml cup of brewed coffee, 63 mg for a single espresso shot, 47 mg for a 240 ml cup of black tea, 34 mg for a 355 ml can of cola and 80 mg for a 250 ml energy drink. These are mid-range values from food composition data; a large coffee-shop cup or a strong cold brew can hold far more.
The total is then compared with the 400 mg per day level that the US FDA and the European Food Safety Authority (EFSA) describe as not generally associated with harmful effects in healthy adults. EFSA also considers single doses of up to 200 mg, about 3 mg per kg of body weight, unproblematic for most adults. Worked example: 2 coffees, 1 espresso and 1 tea give 190 + 63 + 47 = 300 mg, which is 75% of 400 mg. For a 70 kg person that is 300 ÷ 70 = 4.3 mg/kg, and the single-dose guide is 3 × 70 = 210 mg.
| Drink | Serving | Caffeine | Servings to reach 400 mg |
|---|---|---|---|
| Brewed coffee | 240 ml | 95 mg | 4.2 |
| Espresso | 30 ml shot | 63 mg | 6.3 |
| Black tea | 240 ml | 47 mg | 8.5 |
| Cola | 355 ml can | 34 mg | 11.8 |
| Energy drink | 250 ml can | 80 mg | 5.0 |
What the number means for you
The 400 mg figure is a population guideline, not a target. People differ widely in how fast they clear caffeine, and lighter adults reach the same per-kilogram dose with fewer drinks, which is why the per-kg line is shown. EFSA advises a lower ceiling of 200 mg per day during pregnancy and breastfeeding, and for children and teenagers it uses 3 mg per kg of body weight per day rather than a fixed amount.
Common counting errors: treating a large takeaway cup as one cup when it is two or three servings, forgetting pre-workout powders, chocolate or some painkillers that contain caffeine, and counting green or herbal tea as black tea. If you notice palpitations, poor sleep, anxiety or stomach trouble, cut back gradually rather than stopping at once, since sudden withdrawal often brings headaches. Check with a doctor if you are pregnant, have a heart condition or high blood pressure, or take medication that interacts with caffeine.
Frequently asked questions
How many cups of coffee is 400 mg of caffeine?
About four 240 ml cups of brewed coffee at 95 mg each, or six single espresso shots. Large coffee-shop sizes can reach 400 mg in two cups.
How much caffeine per kg of body weight is safe?
EFSA considers single doses up to about 3 mg/kg and daily intake up to 400 mg, roughly 5.7 mg/kg for a 70 kg adult, unproblematic for healthy adults. Lower limits apply in pregnancy.
Does decaf coffee contain caffeine?
A little. A cup of decaf usually has around 2 to 15 mg, so it barely moves the daily total unless you drink a lot of it.