General reference · Tea

How much caffeine is in Black tea?

General estimate — source details not rechecked

This is a general estimate, not a figure for a particular brand. We haven’t rechecked the original USDA entry, its version or the serving conversion yet.

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.

Interactive serving

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Adjusted caffeine total48 mgBased on the selected listed serving.

Where this figure comes from

Source type
Government database
Market
General reference
How we got the amount
Authoritative reference
Source reviewed
21 August 2026

Representative reference value; leaf, water temperature and brew time vary. This link opens the USDA database, not the exact food entry. Treat the serving amount as approximate. The date shown here does not mean we rechecked the original entry on that day.

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 shouldn’t be treated as a personal fact.

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Same category, lower documented dose

Looking for less caffeine?

Here are some drinks in the same category with less listed caffeine. This compares caffeine only, not overall health benefits. Check each drink’s source note before choosing.