How Much Caffeine in Tea? Compare Tea v Coffee & Health Effect

Brewed black tea contains 48 mg of caffeine per 8 oz while brewed coffee contains 96 mg — exactly double, but those numbers are not fixed. Brewing time, water temperature, and the type of leaf or bean all shift how much caffeine ends up in your cup, and those differences matter more than most people assume.

Caffeine in brewed black tea (8 oz): 48 mg ·
Caffeine in brewed coffee (8 oz): 96 mg ·
Caffeine in green tea (8 oz): 33 mg ·
Caffeine in herbal tea (8 oz): 0 mg ·
FDA recommended daily caffeine limit: 400 mg

These verified figures provide a quick reference for comparing caffeine levels across common tea and coffee beverages.

How much caffeine is in tea vs coffee?

Tea and coffee deliver caffeine differently, and the gap is wider than most people assume. The Mayo Clinic reports 48 mg of caffeine in an 8 oz cup of brewed black tea, compared to 96 mg in the same size of brewed coffee — exactly double. But those numbers aren’t fixed.

Caffeine content in brewed black tea

• Bigelow Tea states black tea ranges 30–60 mg per 8 oz (Harvard T.H. Chan School of Public Health)
• Steeping time directly affects extraction: 3 minutes yields less caffeine than 5 minutes

Three facts, one pattern: black tea’s caffeine floor and ceiling span a 2× range, meaning the same box of tea bags can produce very different effects depending on how long you steep.

Caffeine content in brewed coffee

• The U.S. Food and Drug Administration notes that brewed coffee averages 95 mg per 8 oz, but preparation changes everything
• Espresso has higher concentration but smaller serving — a single shot contains roughly 63 mg

What this means: a standard mug of brewed coffee typically delivers about twice the caffeine of a mug of black tea, but both vary enough that a strong tea can match a weak coffee.

Brewing method impact on caffeine extraction

• Tea leaves contain about 4% caffeine by dry weight, while coffee beans range from 0.9–2.6% (Healthline)
• Hot water extracts caffeine more efficiently from coffee beans due to their structure

The trade-off: tea leaves start with more caffeine per gram, but coffee’s brewing method — hotter water, longer contact — pulls more of it into the cup.

Is 2 cups of tea a lot of caffeine?

For most adults, two cups of black tea is comfortably within the safe zone — but context matters. The U.S. Food and Drug Administration sets the daily limit at 400 mg for healthy adults. Two 8 oz cups of black tea deliver about 96 mg total, or roughly one-quarter of that cap.

Daily caffeine limits for adults

• FDA: 400 mg per day is safe for most healthy adults
• Pregnancy reduces the recommended limit to 200 mg per day

For pregnant readers, the math changes: two cups of black tea land at 96 mg — just under half the pregnancy limit — leaving room for a third cup but not much else.

Caffeine sensitivity factors

• Individual tolerance varies based on genetics, body weight, and habitual intake
• Pregnancy, anxiety disorders, and certain medications lower the safe threshold

What this means: two cups of black tea is a moderate caffeine intake for most people, but those with specific health considerations need to account for their total daily caffeine from all sources.

Does caffeine increase cortisol?

Yes — and the timing matters more than most headlines suggest. Research published in PubMed Central shows that caffeine stimulates cortisol secretion, particularly in people who don’t consume it daily.

What are signs of high cortisol?

• Weight gain, especially around the midsection
• Fatigue and sleep disruption
• Mood changes and difficulty concentrating

The pattern: caffeine increases cortisol acutely, but daily users develop partial tolerance — though not complete, as the same study found that 300 mg/day produced incomplete tolerance while 600 mg/day produced more complete suppression.

Will quitting caffeine lower cortisol levels?

• Quitting can lower baseline cortisol over time, per the same PubMed Central study
• After 5 days of abstinence, a single caffeine dose triggered a robust cortisol spike — meaning sensitivity returns quickly

The catch: quitting resets sensitivity, so a return to caffeine will produce a stronger cortisol response than steady daily use.

How much caffeine is in different types of tea?

Not all teas are equal, and the range is wider than many expect. Harvard T.H. Chan School of Public Health reports that black tea leads the category, green tea sits lower, and herbal teas contain none.

Caffeine in Irish tea

• Irish tea is typically a strong black blend, similar to other black teas at 30–60 mg per 8 oz
• Brands like Barry’s and Lyons fall within this range, though exact numbers vary

Caffeine in black tea

• Bigelow Tea states black tea ranges 30–60 mg per 8 oz (Harvard T.H. Chan School of Public Health)
• Darjeeling and Assam can sit at opposite ends of that range

Caffeine in green tea

• BBC Good Food reports green tea averages 33 mg per cup
• Lighter caffeine than black tea, but still enough to affect sensitive individuals

Caffeine in matcha

• Matcha is higher because you consume the whole leaf powder — roughly 70 mg per 8 oz serving
• That’s comparable to a cup of coffee, but with L-theanine for a smoother effect

Caffeine in herbal tea

• All true herbal teas (chamomile, peppermint, rooibos) contain 0 mg caffeine naturally
• Safe for caffeine-sensitive individuals, including during pregnancy

The implication: if you’re looking to reduce caffeine, swapping from black to green tea cuts roughly 30%, while switching to herbal eliminates caffeine entirely.

What drink has the highest caffeine content?

If maximum caffeine per ounce is the goal, brewed coffee leads the common beverages — but energy drinks and espresso challenge that lead in different ways. According to the Mayo Clinic, brewed coffee contains 96 mg per 8 oz — more than double black tea’s 48 mg and triple green tea’s 33 mg.

Beverages ranked by caffeine per ounce

• Espresso: about 63 mg per 1 oz shot (highest concentration)
• Brewed coffee: 96 mg per 8 oz (12 mg/oz)
• Black tea: 48 mg per 8 oz (6 mg/oz)
• Green tea: 33 mg per 8 oz (4.1 mg/oz)
• Soda: 30–40 mg per 12 oz (2.5–3.3 mg/oz)
• Herbal tea: 0 mg

Coffee vs energy drinks vs soda

• Energy drinks like Red Bull contain 80 mg per 8.4 oz — comparable to brewed coffee
• Sodas are the weakest common caffeinated option at 30–40 mg per 12 oz

What this means: a 12 oz soda has less caffeine than a single cup of black tea, making tea a stronger caffeine source than many soda drinkers expect.

Comparison table: caffeine in common beverages

Five common drinks, one pattern: brewed coffee and energy drinks cluster near the top, while tea spans a three-fold range depending on type and brewing.

“Brewed coffee commonly contains more caffeine per typical serving than brewed tea, but the exact amount varies substantially by bean, leaf, brewing method, and serving size.”

— Mayo Clinic

“Green tea averages 33 mg per cup; matcha is higher due to whole leaf powder.”

— BBC Good Food

“Caffeine increases cortisol secretion in humans at rest and during mental stress — and daily intake produces partial but not complete tolerance.”

— PubMed Central

“Tea leaves contain about 4% caffeine vs 0.9–2.6% in coffee beans; hot water extracts more caffeine from coffee.”

— Healthline

Confirmed facts

• Brewed black tea contains 48 mg caffeine per 8 oz (Mayo Clinic)
• Brewed coffee contains 96 mg caffeine per 8 oz (Mayo Clinic)

What’s unclear

• Exact caffeine content in Irish tea varies by brand and preparation
• Cortisol response to caffeine depends on individual tolerance and habitual intake
• Herbal teas may not always be caffeine-free if blended with caffeinated tea leaves
• The 400 mg daily caffeine limit may vary based on individual health conditions and sensitivity

The pattern: tea drinkers have a clear factual foundation for most common questions, but individual variation in both brewing and biology means the exact answer is rarely one-size-fits-all.

For the tea drinker monitoring caffeine intake, the choice is clear: stick with black tea under 4 minutes steep time for moderate caffeine, swap to green tea for a lighter lift, or choose herbal for zero caffeine without sacrificing ritual.