# Black tea vs coffee: how much caffeine?

A mug of black tea is 47 mg of caffeine, about half a cup of black coffee. Where the difference from green tea comes from, and how tea days add up.

## Numbers the app uses

| Field | Value |
| --- | --- |
| Default serving | 240 ml |
| Hydration factor | 1.00 |
| Counts toward the daily goal | 240 ml per serving |
| Caffeine | 47 mg per serving |
| Calories | 1 kcal per 100 ml (2 kcal per serving) |

## Half a coffee, and it adds up quietly

A 240 ml mug of black tea is 47 mg of caffeine, roughly half a cup of black coffee. That comparison is the one people make, and then they stop making it. Nobody counts mugs of tea the way they count coffees. Six mugs across a working day is 282 mg. Three cups of black coffee would have cost you the same. A tea habit and a coffee habit can land in the same place; only one of them feels like a habit.

## Same plant as green tea, different handling

Black tea and green tea come off the same bush, *Camellia sinensis*. Oxidation is what makes the leaves black, and oxidation does not create caffeine. The leaf has what it has. The difference between 47 mg and green tea's 30 mg mostly happens in the mug. Black tea steeps for three to five minutes in water straight off the boil. Green tea brews cooler and briefer, to keep it from turning bitter. Hotter water for longer pulls more caffeine out of the same amount of leaf.

## A splash of milk does not change how it hydrates

Black tea's hydration factor is 1.00, the same as water, with milk or without. A latte and a matcha latte both sit at 1.10. The difference is proportion. Twenty millilitres of milk in a 240 ml mug is under a tenth of the drink. That is too little to slow anything down measurably. A latte, by contrast, is milk with a shot in it. The catalog reserves the 1.10 factor for drinks that are mostly dairy. Your mug counts as exactly 240 ml, milk or no milk.

## 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/black-tea/