How Much Caffeine Is in a Cup of Tea vs Coffee?
A mug of tea has about 47 mg of caffeine, a mug of filter coffee around 140 mg, and an espresso about 65 mg. Brewing time and size change all of these more than people expect.
In short
A typical mug of black tea contains around 47 mg of caffeine, roughly a third of the 140 mg in a mug of filter coffee. A single espresso has about 65 mg, instant coffee around 75 mg per mug, and green tea about 30 mg. Brewing time and cup size shift these figures a lot: a strongly brewed tea can approach a weak coffee.
Tea and coffee are both caffeinated, and the assumption that tea is a gentle alternative is only partly true. It has less, cup for cup, but the gap is narrower than reputation suggests and it depends heavily on how each is made.
Typical figures
| Drink | Typical caffeine |
|---|---|
| Filter coffee, 250 ml mug | 140 mg |
| Coffee-shop large | 200 to 300 mg |
| Espresso, single shot | 65 mg |
| Instant coffee, mug | 75 mg |
| Black tea, mug | 47 mg |
| Green tea, cup | 30 mg |
| Decaf coffee | 2 to 5 mg |
| Cola, 330 ml can | 33 mg |
| Energy drink, 250 ml | 80 mg |
These are averages. Real cups vary by half either way.
Why the numbers move so much
Brewing time. Caffeine extracts steadily. A tea bag dunked for 30 seconds gives perhaps 20 mg; the same bag left for five minutes gives over 60. Coffee behaves the same way, which is why a long pour-over is stronger than a quick one.
Size. A coffee shop’s large is often 400 to 500 ml, which is two mugs. The caffeine scales with it. The figure for a large branded coffee can exceed 300 mg, close to the whole daily guideline in a single cup.
Bean and leaf. Robusta coffee beans carry about twice the caffeine of arabica. Broken tea leaves in bags release caffeine faster than whole leaf.
Water temperature. Hotter water extracts more. Green tea brewed correctly, at around 80°C, gives less caffeine than the same leaves in boiling water.
A point that surprises people
Weight for weight, dry tea leaves contain more caffeine than coffee beans. Tea ends up weaker in the cup because far less leaf is used per serving and it is steeped rather than pressure-extracted. The plant is not gentler; the preparation is.
What it means for sleep
Caffeine has a half-life of five to six hours. A 47 mg tea at 4pm leaves about 24 mg at 9pm, which for most people is tolerable. A 140 mg coffee at 4pm leaves about 70 mg at 9pm, roughly a fresh espresso, and that measurably reduces deep sleep in most adults.
So the practical difference between tea and coffee is less about the morning and more about the afternoon. An afternoon tea is usually fine. An afternoon coffee is a bet.
The daily limit
The European Food Safety Authority considers 400 mg a day safe for healthy adults and 200 mg during pregnancy. Four hundred is about three mugs of filter coffee, or a large coffee-shop drink plus one more, or eight mugs of tea. Individual tolerance varies enormously, driven by a gene that controls how fast the liver clears caffeine, so the limit is a ceiling rather than a target.
If you want the pleasure of the drink in the evening without the sleep cost, decaf coffee or a herbal infusion is the honest answer. A weak tea is a compromise; a decaf is a solution.
Common questions
Does green tea have less caffeine than black?
Usually, at around 30 mg per cup against 47 for black, but the range overlaps because brewing temperature and time matter more than the leaf type. A long-steeped green tea can exceed a briefly dunked black one.
Is decaf caffeine-free?
No. Decaffeination removes most but not all of it, leaving roughly 2 to 5 mg per cup for coffee. That is negligible for most people but not zero for someone highly sensitive.
How much is too much?
Guidance from the European Food Safety Authority puts 400 mg a day as safe for healthy adults, and 200 mg during pregnancy. That is about three mugs of filter coffee or eight of tea. Sensitivity varies enormously between people.
Sources
Every factual claim above traces to one of these. Follow them rather than taking this article's word for it.
- Caffeine safety assessment European Food Safety Authority
- Spilling the beans: how much caffeine is too much US Food and Drug Administration
- Caffeine and sleep Sleep Foundation
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