Caffeine in drinks: coffee, tea and energy drinks
The caffeine in a drink depends on both concentration and serving size. Use the product label or supplier's information when possible; a generic “cup of coffee” is only an estimate.
Approximate caffeine by serving
These examples come from EFSA's caffeine guide. They describe particular portions, not every product in that category.
| Drink | Serving | Approximate caffeine |
|---|---|---|
| Espresso | 60 ml | 80 mg |
| Filter coffee | 200 ml | 90 mg |
| Black tea | 220 ml | 50 mg |
| Cola | 355 ml | 40 mg |
| Energy drink | 250 ml | 80 mg |
How to read a per-100-ml label
Multiply caffeine per 100 ml by the number of 100 ml portions you drink. For example, a hypothetical label showing 30 mg per 100 ml means 150 mg in 500 ml. Do not confuse the amount per serving with the amount per container.
Record the amount you consumed. If you leave half a bottle, logging the full bottle will overstate your input. For a basic method, see how to track caffeine intake.
Coffee and tea need extra context
A café's serving information is more useful than a generic name. Note the cup size and any extra shots. For home preparation, record the estimate you used consistently and recognise that preparation can vary. A precise-looking milligram entry is only as reliable as its source.
Energy drinks and pre-workout
Check the label for total caffeine and the defined serving. A scoop, a serving and a whole container are not necessarily the same thing. Avoid applying the example energy-drink value above to a supplement. If the caffeine amount is unavailable, ask the manufacturer instead of entering a guessed zero.
Does decaf still count?
Decaf does not necessarily mean caffeine-free. The FDA gives a typical range of 2–15 mg for an 8-fluid-ounce decaf coffee. Use a product-specific value when you have one.
From a label to a bedtime estimate
Once you have the caffeine amount and consumption time, use the caffeine calculator to explore what may remain. Our half-life guide explains the calculation, and the sleep guide explains why a result is not a sleep guarantee.