Green Tea Caffeine: A Comprehensive Breakdown

A standard 240 ml cup of brewed green tea contains 28 mg of caffeine.

• 240 ml brewed green tea = 28 mg caffeine (11.7 mg/100 ml).
• Matcha (1 tsp, whisked) = 70 mg, about 2.5× brewed green tea.
• Typical brewed coffee (drip) 240 ml = 96 mg200 mg for context.
• Population-average caffeine half-life ≈ 5.7 hours; after 6 h ~48% remains.

Caffeine levels in standard green tea

The dataset value for a 240 ml (about 8 fl oz) cup of brewed green tea is 28 mg (11.7 mg per 100 ml). That number reflects a typical single steep using loose leaf or a tea bag at standard strength. Compared with other common hot teas in the dataset: black tea 240 ml = 47 mg, oolong = 37 mg, white tea = 16 mg.

Variations across green tea types

Not all green teas are equal. Matcha is powdered whole-leaf tea and delivers the full leaf’s caffeine to the cup—dataset: matcha (1 tsp) = 70 mg. Other named varieties (sencha, gyokuro, bancha) aren’t individually listed in the dataset; their caffeine content depends on leaf choice and preparation. Shade-grown teas (gyokuro) typically concentrate caffeine and L-theanine compared with sun-grown leaves, so expect higher values than 28 mg per 240 ml.

Quick comparison table (dataset values)

Factors that change green tea caffeine

Primary variables are leaf type, leaf-to-water ratio, water temperature, steep time and whether you consume the leaf (matcha) or just the infusion. Longer steeping and hotter water extract more caffeine; doubling leaf mass roughly doubles caffeine. Because matcha is powdered whole-leaf, its concentration is higher than a typical infusion of the same volume.

Practical preparation guidance

• To reduce caffeine: use cooler water, shorter steeps (30–60 seconds), or choose white tea (dataset: 16 mg/240 ml).
• To increase caffeine: use more leaf, hotter water, longer steeps, or choose matcha (70 mg) or yerba mate (85 mg).

How caffeine from green tea decays in the body

Caffeine follows first-order elimination with a population-average half-life of about 5.7 hours. That means the amount in your body drops by roughly half every 5.7 hours. Below are concrete remaining-milligram calculations from two real doses in the dataset: 28 mg (brewed green tea) and 70 mg (matcha).

Example: after a 240 ml cup of green tea (28 mg), roughly 14 mg remains after 6 hours and about 7 mg after 12 hours. For matcha (70 mg), about 34 mg remains at 6 hours and 17 mg at 12 hours. Individual half-life varies with age, genetics, pregnancy, liver function and concurrent medications.

Health context, safety limits and timing

Authoritative guidance: the U.S. FDA notes about 400 mg/day as a reference upper bound for healthy adults; many organizations advise lower intakes during pregnancy (≈200 mg/day) and the American Academy of Pediatrics discourages caffeine for adolescents. A single cup of brewed green tea (28 mg) is low compared with these limits, but multiple cups or matcha servings can add up.

Practical timing: because about half the caffeine remains after ~6 hours, avoid consuming concentrated green tea (matcha or multiple cups) within 6 hours of your planned bedtime if you are sensitive to sleep disruption. If tracking cumulative intake matters, log servings in an app such as CoffeeLog to see daily totals and timing.

Green tea extracts and supplements

Green tea extracts concentrate polyphenols and sometimes caffeine; the dataset does not list specific extract doses, so read labels. Extracts can deliver substantially more caffeine per serving than a brewed cup, and some high-dose extracts have been associated with rare liver injury reports—consult healthcare professionals before starting high-dose supplements. Always track supplement milligrams the same way you track beverages.

Takeaway and tracking

Brewed green tea is low in caffeine (28 mg/240 ml) compared with coffee. Matcha is meaningfully higher (70 mg per 1 tsp). Use steeping choices to tune caffeine up or down, and remember caffeine lingers: roughly half remains after 5.7 hours. For precise daily totals and timing, log drinks and supplements in CoffeeLog or a similar tracker.

Sources and authorities cited

Data points above come from beverage composition entries (USDA FoodData Central-style dataset) and are presented alongside clinical guidance from the U.S. Food and Drug Administration, European Food Safety Authority, Mayo Clinic and American Academy of Pediatrics for safety context.

How much caffeine will be caffeine be in my body after drinking two cups of green tea?

Two standard 240 ml cups of brewed green tea deliver 56 mg of caffeine immediately; that value comes from the dataset (28 mg per 240 ml cup, per USDA FoodData Central).

Using a first-order elimination model with a population-average half-life of 5.7 hours (decay model used here), about 56 × 0.5^(6/5.7) ≈ 56 × 0.485 ≈ 27 mg remains after six hours and roughly 56 × 0.5^(12/5.7) ≈ 56 × 0.235 ≈ 13 mg remains after twelve hours.

Double serving is two standard 240 ml cups.

Step-by-step arithmetic helps: start = 2 × 28 mg = 56 mg (USDA FoodData Central); fraction remaining after 6 h = 0.5^(6/5.7) ≈ 0.485; remaining = 56 × 0.485 ≈ 27 mg. If you want a live readout for a specific clock time, use our caffeine half-life calculator to enter dose times and see mg left now.

How many brewed green tea cups equal one matcha serving in caffeine?

One 1-tsp matcha serving has 70 mg of caffeine and a 240 ml brewed green tea cup has 28 mg, per USDA FoodData Central, so one matcha equals 70 ÷ 28 = 2.5 brewed cups by milligrams.

Put another way: two brewed cups (56 mg) still fall short of a single matcha (70 mg), while three brewed cups (84 mg) exceed it.

Equivalence is a straight milligram comparison.

That 2.5× rule is useful when choosing between matcha and brewed tea for a target milligram dose; see our matcha guide for menu examples at Matcha Caffeine: Understanding Your Green Tea Boost and the general green tea guide at Green Tea Caffeine: Comprehensive Nutrition Guide.

Can I mix matcha and coffee, and how do I total the caffeine safely?

You can add milligrams from different drinks: for example, a 1-tsp matcha (70 mg) plus a 240 ml drip coffee (96 mg) totals 166 mg immediately, using dataset values from USDA FoodData Central.

To judge safety, compare cumulative milligrams to guidance: the U.S. FDA cites about 400 mg/day as a general reference upper bound for healthy adults, and the European Food Safety Authority sets 200 mg/day as a pregnancy recommendation (see U.S. FDA and EFSA 2015).

Cumulative intake is the simple sum of milligrams consumed.

Practical example and caveats: 70 mg (matcha) + 96 mg (drip coffee) = 166 mg; if you add a 250 ml Red Bull (80 mg) later the day, total = 246 mg (all dataset values per USDA FoodData Central), still under 400 mg but above EFSA pregnancy guidance of 200 mg/day. Use our safe daily limit tool to see personalized thresholds by body weight and the Caffeine Dosage Guide for situational advice.

How should I estimate caffeine if I make a more concentrated green tea (double leaf or long steep)?

If you double the leaf mass for a given 240 ml cup you should expect roughly double the caffeine: a double-strength brewed cup would approximate 56 mg (2 × 28 mg), per the dataset base value and the general extraction rule that doubling leaf mass roughly doubles caffeine.

For timing effects, the same 5.7-hour half-life model applies to concentrated brews: a 56 mg concentrated cup would leave about 56 × 0.5^(6/5.7) ≈ 27 mg after six hours (decay model used here).

Concentrated brew is a larger leaf-to-water ratio for the same cup volume.

Practical caveats: hotter water and longer steep times extract more caffeine, so the linear scaling with leaf mass is approximate; if you routinely brew stronger cups, log them as 2× or 3× servings in your tracker (for example, CoffeeLog or our half-life calculator) to get accurate cumulative totals.

How do I track multiple green tea servings spread across a workday to estimate what’s left before bedtime?

Add milligrams for each serving and apply the first-order decay to each dose separately; for example, three brewed green teas at 09:00, 13:00 and 17:00 equal 3 × 28 = 84 mg initial total (USDA FoodData Central), but at 23:00 the remaining amount is the sum of each dose’s decay from its intake time.

Specifically, remaining = 28×0.5^((23−9)/5.7) + 28×0.5^((23−13)/5.7) + 28×0.5^((23−17)/5.7) ≈ 28×0.5^(14/5.7) + 28×0.5^(10/5.7) + 28×0.5^(6/5.7) ≈ 28×0.06 + 28×0.18 + 28×0.485 ≈ 1.7 + 5.0 + 13.6 ≈ 20.3 mg remaining at 23:00, using the decay model and half-life 5.7 hours (decay model used here).

Separate-dose decay is dose-by-dose elimination.

Use our last cup before bed tool to enter actual times and see the recommended cutoff based on the Drake et al. sleep study that found caffeine taken 6 hours before bedtime reduced sleep by more than an hour (Drake et al., 2013), and combine that with the per-cup numbers from USDA FoodData Central.

Bottom line

A standard 240 ml brewed green tea contains 28 mg of caffeine and matcha (1 tsp) contains 70 mg, both values from USDA FoodData Central; caffeine follows first-order elimination with a population-average half-life of about 5.7 hours (decay model used here), so roughly half the caffeine remains after ~6 hours.

Concrete takeaways: one brewed cup = 28 mg; one matcha = 70 mg (so matcha ≈ 2.5 brewed cups). Use the decay formula remaining = D × 0.5^(hours/5.7) to convert a dose into milligrams left at later times (for example, a single 28 mg cup leaves ≈14 mg after 6 hours and ≈7 mg after 12 hours). For daily safety compare summed milligrams to authoritative guidance: the U.S. FDA cites about 400 mg/day for healthy adults (U.S. FDA) and EFSA recommends a 200 mg/day limit during pregnancy (EFSA 2015).

If you mix drinks, add the dataset milligrams (for example, matcha 70 mg + drip coffee 96 mg = 166 mg, USDA FoodData Central) and compare the total to those guidance numbers; to plan timing around sleep, remember Drake et al. (2013) showed caffeine taken 6 hours before bedtime still reduced sleep, so avoid concentrated green tea or multiple servings in that pre-bed window where sleep matters (Drake et al., 2013). For exact personal arithmetic, use our caffeine half-life calculator, the safe daily limit tool, or the last cup before bed helper to convert servings and times into mg remaining.