# Energy drink caffeine: how much is in one can

A 250 ml energy drink carries 80 mg of caffeine and 113 calories, and still counts as 250 ml of water. What that means for your day.

## Numbers the app uses

| Field | Value |
| --- | --- |
| Default serving | 250 ml |
| Hydration factor | 1.00 |
| Counts toward the daily goal | 250 ml per serving |
| Caffeine | 80 mg per serving |
| Calories | 45 kcal per 100 ml (113 kcal per serving) |

## The caffeine is the point, the sugar is the surprise

80 mg in 250 ml works out at 320 mg of caffeine per litre. That number matters
because European labelling rules draw a line at 150 mg per litre. Any drink
over it must carry the words "High caffeine content. Not recommended for
children or pregnant or breast-feeding women." A standard energy drink sits at
roughly twice that threshold, which is why the warning appears on almost every
can.

The 500 ml cans that dominate fridge shelves are two servings, not one. Log one
of those and the app charges you 160 mg. That is more caffeine than a 355 ml
mug of drip coffee. A mid-afternoon can of that size is still measurably in
your blood at bedtime. That is the number the "last chance for coffee" feature
is built around. It works backwards from when you want to sleep and the
half-life you picked. Then it tells you when the next dose stops being free.

## Why it still counts as a full glass of water

The hydration factor is 1.00, so 250 ml of energy drink adds 250 ml toward the
daily goal. Caffeine at these doses is not a meaningful diuretic. The Beverage
Hydration Index trial measured urine output after a litre of each of thirteen
drinks. The caffeinated ones (cola, tea, coffee) sat level with water. Nothing
in the rest of the can changes that. Taurine, glucuronolactone and the B
vitamins are there for the marketing story. None of them alters fluid balance.

What does change is everything you are drinking alongside the water. 113
calories per can is almost all sugar, roughly the same as an equal volume of
cola. It arrives without any of the bulk that makes food feel like food.
Sugar-free cans keep the caffeine and drop the calories. If that is what is in
your hand, edit the calorie figure on the drink, and the app remembers it.

## A practical way to use the numbers

Caffeine here scales with volume, not with cups. Half a can is 40 mg, a 500 ml
can is 160 mg, a 355 ml can is 114 mg. Slide the serving control above to the
size actually in front of you. Then decide whether it fits under your ceiling
for the day. Most people who cut back do it by switching the second can for a
smaller one rather than by giving the habit up.

## Source

Hydration factors follow the Beverage Hydration Index. Maughan RJ, Watson P, Cordery PA, et al. “A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index.” American Journal of Clinical Nutrition, 2016;103(3):717-723. https://pubmed.ncbi.nlm.nih.gov/26702122/

Page: https://waterchamp.app/drinks/energy-drink/