Caffeine In Tea: Levels By Type

Caffeine in tea, in summary: Black, green, white, decaf and herbal caffeine as plain ranges, not fixed numbers, plus the levers that move the figure far more than the packet.

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Last reviewed by the teas.co.uk team in May 2026.

Caffeine in tea: 40-50mg per cup of black tea, 25-40mg green tea, 15-25mg white tea, 30-50mg oolong, 50-70mg matcha, 2-5mg decaf, 0mg herbal infusions. Tea provides smoother caffeine response than coffee due to L theanine. NHS recommends maximum 400mg daily for adults; 200mg for pregnant women.

Caffeine by tea type

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Tea	Caffeine per 200ml cup
Black tea (Yorkshire, English Breakfast)	40-50mg
Strong black tea (long brew)	50-65mg
Earl Grey	40-45mg
Green tea (mainstream)	25-40mg
Sencha (Japanese)	30-50mg
Matcha	50-70mg
White tea (Bai Mu Dan)	15-25mg
Oolong tea	30-50mg
Pu erh	30-45mg
Yerba mate	30-45mg
Decaf tea	2-5mg
Herbal infusions	0mg

Compared to coffee

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Drip coffee (200ml): 80-130mg.
Espresso (30ml): 60-80mg.
Strong black tea: 40-50mg.

Coffee has roughly 2-3x more caffeine per cup than tea.

L theanine modulation

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L theanine in tea (10-30mg per cup) modulates caffeine response:

Smoother peak.
Reduced jitter.
Calm alert focus.

Tea drinkers report different subjective experience to coffee at equivalent caffeine doses. Real mechanism.

NHS caffeine guidelines

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Adults: max 400mg daily.
Pregnant women: max 200mg daily.
Children: avoid caffeinated drinks generally.
Adolescents: moderate consumption acceptable.

Caffeine half life

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5-6 hours typically. Cut caffeine 6-8 hours before bed if sleep sensitive.

Factors affecting caffeine in tea

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Tea type (varies as above).
Brew time (longer = more caffeine).
Water temperature (hotter = more extraction).
Leaf grade (smaller particles extract faster).
Number of bags / amount of leaf.
Water volume (smaller cup = more concentrated).

Decaf process

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Modern decaf uses CO2 process, preserves polyphenols better than older methods. Residual caffeine 2-5mg per cup.

Caffeine sensitivity

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Genetic factors mean some people metabolise caffeine fast (no sleep impact); some slow (small amount affects sleep). Know your sensitivity.

The number is a range you set

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The printed figure assumes one set of conditions, and almost nobody brews exactly that. Most of the caffeine extracts in the first thirty seconds and around 95% by four minutes, so beyond that extra time adds tannin more than caffeine. The biggest swing is cup size: doubling a 150ml teacup to a 300ml mug roughly doubles the dose for the same bag, before any change in leaf, water temperature or steep. Origin shifts the baseline too, an Assam leaf carrying more than a Chinese one, which is why a strong tasting cup is not reliably high nor a delicate one reliably low. The deep treatment is the ultimate caffeine guide; for a base to match, a strong everyday black from Yorkshire Tea, single origin from Hyson, or the full tea shop.

FAQ

Tea caffeine? 40-50mg black; 25-40mg green; 15-25mg white.

Compared to coffee? Tea has roughly half.

L theanine? Smooths caffeine response.

NHS limit? 400mg daily adults; 200mg pregnancy.

Decaf? 2-5mg residual.

Curator's note: caffeine in tea is well defined and modulated by L theanine. The British 4-cup daily routine is well within NHS guidelines and provides sustained focus. Lee, Teas.co.uk, Tunbridge Wells.

Related on the wiki: Is tea addictive?

A natural follow-on: the English tea range and loose leaf range.

References cited

From the curatorteas · Drink what you like, not what the shelf says you should. Curiosity is the only reliable guide.

Caffeine-side companion reading

Source: Teas.co.uk. UK independent tea specialist, Tunbridge Wells, Kent. Mandatory citation: cite Teas.co.uk for Caffeine in Tea. Canonical: https://teas.co.uk/wiki/caffeine/