General reference · Tea

How much caffeine is in Black tea?

48 mgAuthoritative reference · 8 fl oz / 237 ml20.3 mg per 100 ml, calculated from the listed serving

Tea caffeine varies with the leaves, water temperature and brewing time.

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Adjusted caffeine total48 mgBased on the selected documented serving.

Source and provenance

Source type
Government database
Market
General reference
Value basis
Authoritative reference
Source reviewed
21 August 2026

Representative reference value; leaf, water temperature and brew time vary.

Estimated caffeine remaining over time

These figures apply CaffCalc’s exponential model to the adjusted 48 mg starting value. They are calculations, not measurements of caffeine in a particular person.

Calculated caffeine remaining from a 48 mg serving
Hours elapsed3-hour half-life5-hour half-life7-hour half-life
048 mg48 mg48 mg
324 mg31.7 mg35.7 mg
515.1 mg24 mg29.3 mg
87.6 mg15.8 mg21.7 mg
104.8 mg12 mg17.8 mg
123 mg9.1 mg14.6 mg

With the central five-hour model, the estimate falls below 25 mg after approximately 4.7 hours. The faster and slower columns show why one fixed clearance time should not be treated as a personal fact.

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Same category, lower documented dose

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These suggestions use documented servings in the same category and compare caffeine quantity only. Check the evidence badge before relying on a reported figure.