How Much Caffeine in Tea – Complete Guide by Type, Brew and Safety

A single cup of tea can contain anywhere from 15 to 140 milligrams of caffeine, depending on the type, how it is brewed, and the specific product. For most healthy adults, a daily intake of up to 400 mg of caffeine is generally considered safe, but the exact amount in a cup of tea is never a fixed number.

All true teas—black, green, white, oolong, and matcha—come from the same plant, Camellia sinensis, which naturally contains caffeine. The variation in caffeine content from one cup to the next is influenced by the tea variety, the size of the tea leaves, the water temperature, and the steeping time. Herbal infusions like rooibos or mint are the only truly caffeine-free options.

Understanding these differences helps drinkers choose the right tea for the right moment, whether they are looking for a gentle morning boost or a low-caffeine evening drink.

How Much Caffeine Is in a Cup of Tea? (By Type)

• Tea leaves contain more caffeine by dry weight than coffee beans, but the final cup has less because you use less leaf.
• Matcha contains significantly more caffeine than steeped green tea because you consume the whole leaf.
• Adding milk does not remove caffeine; calcium caseinate may slightly hinder absorption but not reduce total mg.
• The ‘calm alert’ from tea is due to L-theanine, not a lack of caffeine.
• White tea is not caffeine-free, despite a common myth; it contains low but measurable amounts.
• Brewing time is a major factor: longer steeping extracts more caffeine.
• Herbal teas like rooibos and mint are naturally caffeine-free.

Tea vs. Coffee: Which Has More Caffeine?

Cup for cup, brewed coffee contains significantly more caffeine than tea. A standard 8-ounce cup of filter coffee averages around 95 mg of caffeine, while the same amount of black tea contains roughly 47 mg. However, this comparison is not as simple as it seems.

The Mayo Clinic Caffeine Content Chart shows that espresso has 30–90 mg per 1.5-ounce shot, while filter coffee can reach 179 mg per cup. A mug of filter coffee can contain 140 mg, while instant coffee offers about 100 mg per serving, according to Tommy’s. In contrast, a mug of tea from a bag is listed around 75 mg.

As noted by BBC Good Food, a cup of green tea averages 33 mg of caffeine. The HSE adds that the amount in both tea and coffee depends heavily on the brand, brewing time, and method. A strong cup of black tea can occasionally rival a weak cup of coffee, but this is uncommon.

The key difference in effect, as noted by Healthline, is the presence of L-theanine in tea, an amino acid that promotes a state of calm alertness, modifying the jittery feeling often associated with coffee’s higher caffeine dose.

Does tea have less caffeine than coffee?

Generally, yes. A typical serving of tea contains roughly half the caffeine of a comparable serving of drip coffee. But when comparing a large mug of strong black tea to a small cup of instant coffee, the values can be surprisingly close.

Does How You Brew Your Tea Change the Caffeine Level?

The brewing process is one of the most underestimated variables in caffeine content. The same tea leaves can produce a cup with very different caffeine levels depending on how they are handled.

Does brewing time affect caffeine content?

Yes. A study published in the BMJ and indexed by the PMC states that tea brewed for more than 3 minutes contains about 20% more caffeine than the baseline estimate. The HSE also notes that longer steeping times result in higher caffeine extraction. A quick 1-minute steep will yield a noticeably lower caffeine dose than a 5-minute steep.

Does adding milk to tea reduce the caffeine?

Milk does not meaningfully reduce the total amount of caffeine in a cup of tea. None of the available health sources suggest that adding milk removes caffeine. The main effect of milk is to change the taste and dilute the liquid, but the caffeine molecule itself remains in the tea. The amount of caffeine in the cup is still the relevant factor.

Is the Caffeine in Tea Safe? (Pregnancy & Daily Limits)

For healthy, non-pregnant adults, the FDA states that up to 400 mg of caffeine per day is generally not associated with dangerous negative effects. Drinking tea well within this limit is considered safe for most people.

Is it safe to drink caffeinated tea during pregnancy?

Guidance from multiple health authorities advises pregnant women to limit their total daily caffeine intake. The HSE recommends no more than 200 mg/day, while a French pregnancy resource suggests keeping intake under 300 mg/day. There is a general consensus that limiting caffeine is prudent, but the precise threshold varies slightly by organization.

The HSE and Tommy’s both note that high caffeine intake during pregnancy has been linked to low birth weight and, in some studies, an increased risk of miscarriage. The NHS provides official caffeine guidance for pregnancy. ACOG’s committee opinion, summarized in a Boston University article, states that fewer than 200 mg/day is considered safe by most experts.

It is also worth noting that coffee and tea are best consumed between meals, as they can interfere with iron and calcium absorption when taken during or immediately after eating.

Tea vs. Soda & Other Drinks: A Caffeine Comparison

When comparing tea to other popular caffeinated beverages, the differences are notable. A standard 12-ounce can of Coca-Cola contains about 34 mg of caffeine, which is comparable to a cup of green tea (20–45 mg). A cup of black tea (40–70 mg) usually contains more caffeine than a can of soda, but less than a standard cup of coffee.

Energy drinks are a different category entirely. A typical 8-ounce energy drink can contain between 80 and 150 mg of caffeine, often exceeding a cup of black tea and sometimes rivaling coffee. Given that many energy drinks are sold in larger cans or bottles, the total caffeine per container can be very high.

The practical takeaway is that for a moderate caffeine dose, a cup of black tea or green tea is a lower-caffeine alternative to coffee and energy drinks, but it is not a no-caffeine option. Anyone tracking their total daily intake needs to account for each source.

What Is Certain and What Remains Uncertain About Caffeine in Tea?

The scientific understanding of tea’s caffeine content has some clear certainties and a few areas where the picture is less complete.

Established information: All true teas (Camellia sinensis) contain caffeine. Black tea generally has more caffeine than green and white tea. Matcha has significantly more caffeine than steeped green tea. Caffeine content varies by brand, leaf particle size, and steeping time.

Information that remains unclear: The exact milligram amount of ‘a cup of tea’ varies dramatically by brand (e.g., PG Tips vs. a generic bag vs. loose leaf). Clinical evidence on milk reducing caffeine absorption is mixed and likely shows a small effect at most. Pregnancy thresholds (200 mg/day) are guidelines, not hard limits, and individual metabolism varies significantly.

Why Does Tea Produce a Different Feeling Than Coffee?

The distinct “calm alertness” reported by tea drinkers, compared to the sharper jolt from coffee, is primarily due to the interaction between caffeine and an amino acid called L-theanine. Tea leaves naturally contain L-theanine, which crosses the blood-brain barrier and promotes alpha brain wave activity, associated with a state of relaxed focus.

Cold brew tea also has different caffeine extraction dynamics. When brewed with cold water over several hours, the extraction of caffeine is slower and may result in a different chemical profile compared to hot steeping, though the total caffeine content can still be significant over long extraction periods.

Sources and Credibility: What the Experts Say

“Up to 400 mg of caffeine a day appears to be safe for most healthy adults.”

Mayo Clinic (Feb 2025)

“Green tea contains less caffeine than black tea, with on average 33 mg per cup.”

BBC Good Food / Nutritionist

“All tea (except fruit and herbal infusions) contains caffeine, since it comes from the same plant (Camellia sinensis).”

Whittard Tea

How Much Caffeine Is Right for You?

The amount of caffeine that is right for one person depends on their health status, pregnancy, and individual sensitivity. For most people, a cup of black tea (around 47 mg) or green tea (around 28 mg) fits comfortably within general limits. Those who are pregnant should stick to the guidance of their healthcare provider, commonly under 200 mg per day. For anyone looking to reduce their intake without giving up the ritual, decaffeinated tea or a short-steeped white tea are good alternatives. See our comparison of caffeine content in black tea vs. green tea for more detail.

Frequently Asked Questions