A standard 8-ounce cup of brewed green tea contains about 29 mg of caffeine. That’s roughly a third of what you’d get from a cup of coffee and noticeably less than black tea. But “green tea” covers a wide range of products, and the actual caffeine in your cup can land anywhere from 10 mg to over 60 mg depending on the type of tea, how you brew it, and even how the leaves were grown.
Green Tea vs. Coffee and Black Tea
Green tea sits at the low end of the caffeine spectrum for brewed drinks. An 8-ounce cup of brewed coffee typically delivers 80 to 100 mg of caffeine, meaning you could drink three or four cups of green tea and still take in less caffeine than a single coffee. Black tea falls in the middle at roughly 47 mg per cup. For context, the FDA considers up to 400 mg of caffeine per day safe for most adults, so even a dedicated green tea habit is unlikely to push you near that ceiling.
Caffeine by Type of Green Tea
Not all green teas are created equal. The variety you choose can shift the caffeine content dramatically, sometimes by a factor of ten or more.
Gyokuro, a premium Japanese green tea grown under shade for several weeks before harvest, tops the list at around 160 mg per 100 grams of brewed tea. That’s comparable to coffee. The shade forces the plant to produce more caffeine and other compounds in its leaves, which is why gyokuro tastes richer and hits harder than everyday green tea.
Sencha, the most common Japanese green tea, contains about 20 mg per 100 grams of brewed tea. Hojicha, a roasted green tea with a toasty flavor, comes in at roughly the same level despite tasting quite different. Genmaicha, which blends green tea with toasted rice, has the least caffeine at about 10 mg per 100 grams because the rice dilutes the tea leaf content.
Where Matcha Fits In
Matcha is a special case. Because you’re whisking powdered whole tea leaves into water and drinking everything (rather than steeping and discarding the leaves), you consume more of the leaf’s total caffeine. A gram of matcha powder contains 19 to 44 mg of caffeine. A typical ceremonial serving uses about 2 grams, which puts a bowl of matcha at roughly 38 to 88 mg. A café-style matcha latte often uses even more powder. If you’re choosing green tea specifically for its lower caffeine, a strong matcha can surprise you by rivaling a cup of coffee.
Why the Range Is So Wide
Several factors determine how much caffeine ends up in your cup, starting before the tea is even harvested.
Leaf age: Younger leaves and buds contain significantly more caffeine than older, mature leaves. Caffeine concentration drops as you move from the bud to the first leaf and then the second leaf on the branch. Premium teas made from early spring harvests (sometimes called “first flush”) tend to be higher in caffeine than later picks made from tougher, more mature leaves.
Shade growing: Tea plants grown under shade, like those used for gyokuro and high-grade matcha, ramp up caffeine production in response to reduced sunlight. This is one reason shade-grown teas can contain several times the caffeine of sun-grown varieties.
Leaf size in your cup: Tea bags often contain finely ground dust and small leaf fragments (called fannings) rather than whole leaves. These tiny particles have more surface area exposed to water, so they can release caffeine faster and more completely than whole loose leaves, especially on the first steep. If you’re comparing a tea bag to a loose leaf version of the same tea, the bag may deliver a slightly more caffeinated cup.
How Brewing Changes Your Caffeine
The two biggest variables you control at home are water temperature and steeping time. Research on caffeine extraction shows that most of the caffeine dissolves within the first three minutes of steeping. At 167°F (75°C), a typical recommended temperature for green tea, caffeine levels reach about 10 mg per 100 ml after three minutes and don’t rise much after that. Bump the water to 185°F (85°C) and the three-minute extraction climbs to roughly 11.4 mg per 100 ml.
The practical takeaway: steeping longer than three minutes adds bitterness without adding much more caffeine. And using cooler water (closer to 160°F) will pull slightly less caffeine out of the leaves, which matters if you’re sensitive to it. If you want a lighter cup, a shorter steep at a lower temperature is the simplest adjustment.
Decaf Green Tea Still Has Some Caffeine
If you’re avoiding caffeine entirely, decaffeinated green tea gets you close but not all the way there. Standard decaffeination processes remove about 83% of the caffeine from tea leaves, leaving a small residual amount. A cup of decaf green tea typically contains 2 to 5 mg of caffeine. That’s negligible for most people, but worth knowing if you’re highly sensitive or avoiding caffeine for medical reasons.
Quick Caffeine Comparison
- Genmaicha (8 oz): ~10 mg
- Sencha (8 oz): ~20 mg
- Hojicha (8 oz): ~20 mg
- Standard brewed green tea (8 oz): ~29 mg
- Matcha (2 g serving): 38–88 mg
- Gyokuro (8 oz): up to 120+ mg
- Brewed black tea (8 oz): ~47 mg
- Brewed coffee (8 oz): 80–100 mg
These numbers represent typical ranges, not fixed values. Your cup could fall above or below depending on the specific product, leaf quality, and how you prepare it. The most reliable way to know exactly what you’re getting is to check the label on packaged teas, which often list tested caffeine amounts per serving.