A standard 8-ounce cup of tea contains roughly 15 to 70 milligrams of caffeine, depending on the type. That’s significantly less than brewed coffee, which averages about 96 mg per cup. But the range is wide, and the amount you actually get depends on what tea you’re drinking, how hot your water is, and how long you let it steep.
Caffeine by Tea Type
All true teas come from the same plant, and the differences in caffeine largely reflect how the leaves are processed and oxidized. Here’s what you can expect from an 8-ounce cup brewed at home:
- Black tea: 40 to 70 mg, with a USDA average of about 47 mg
- Oolong tea: 30 to 55 mg
- Green tea: 20 to 45 mg, with a USDA average of about 28 mg
- White tea: 15 to 40 mg
These ranges overlap quite a bit. A strong green tea can deliver more caffeine than a lightly brewed oolong. The category gives you a ballpark, but your brewing method matters just as much.
Matcha Is a Different Story
Matcha is ground whole green tea leaves dissolved in water, so you’re consuming the entire leaf rather than just an infusion. A typical serving uses 2 to 4 grams of powder, which translates to roughly 38 to 176 mg of caffeine. That upper end rivals a cup of coffee. If you’re using a half teaspoon (about 2 grams), you’ll land closer to 40 to 80 mg. A full teaspoon pushes you well above what any steeped tea delivers.
How Steeping Changes Your Cup
Water temperature and steeping time are the two biggest levers you control. Research published by the American Chemical Society measured caffeine extraction at three temperatures and found dramatic differences. At boiling (100°C), a tea bag released about 25 mg of caffeine after just one minute and peaked around 47 mg at six minutes. At a lukewarm 50°C, the same tea only reached about 37 mg even after eight minutes. And at room temperature (20°C), eight minutes of steeping extracted just 17 mg.
The practical takeaway: hotter water and longer steeping times pull more caffeine out of the leaves. If you want less caffeine from the same tea, use cooler water and shorter steeps. If you want more, use boiling water and let it sit for five to six minutes. Beyond that point, caffeine extraction plateaus and you mostly just increase bitterness.
Why Tea Feels Different Than Coffee
Many tea drinkers describe a calmer, steadier alertness compared to coffee, even at similar caffeine doses. This isn’t just perception. Tea contains an amino acid called L-theanine that appears to change how caffeine affects you.
In controlled studies, researchers found that tea produced measurably different responses than coffee even when both drinks contained the same amount of caffeine. In one study, participants drinking tea with 72 mg of caffeine showed lower cortisol (the body’s primary stress hormone) and reported feeling more relaxed compared to a control group receiving the same caffeine dose without tea’s other compounds. That’s notable because caffeine on its own typically raises cortisol, especially under stress. The L-theanine in tea appears to work in the opposite direction, smoothing out the jittery edge that coffee drinkers sometimes experience.
Tea vs. Coffee: A Direct Comparison
An 8-ounce cup of brewed coffee delivers about 96 mg of caffeine, according to Mayo Clinic data. A cup of black tea averages 48 mg. So coffee contains roughly twice the caffeine of the strongest common tea, and three to four times more than green or white tea. In practical terms, you could drink two to three cups of black tea before matching a single cup of coffee.
The FDA considers up to 400 mg of caffeine per day a safe amount for most healthy adults. That’s about eight cups of black tea or four cups of coffee. Most tea drinkers stay well within that range without thinking about it.
What Affects Caffeine in the Leaf Itself
Before your tea is even packaged, the plant’s growing conditions have already shaped its caffeine content. Tea plants grown in more shade tend to produce higher caffeine concentrations in their leaves. This is one reason shade-grown Japanese teas like gyokuro and matcha are higher in caffeine than their sun-grown counterparts. Research on tea plants found that caffeine content drops notably once plants receive more than about 70% of full sunlight. Season matters too: summer-harvested leaves measured slightly higher in caffeine (about 32 mg per gram of dry leaf) than spring-harvested leaves (about 29 mg per gram).
Younger leaves and buds also contain more caffeine than older, larger leaves. Teas made from tips and buds, like some white teas and first-flush black teas, can surprise people with higher-than-expected caffeine despite their delicate flavor.
Decaf Tea Still Has Some Caffeine
Decaffeinated tea isn’t completely caffeine-free. By law, tea labeled “decaffeinated” must have less than 2.5% of its original caffeine content, which typically works out to less than 2 mg per cup. That’s a negligible amount for most people, but worth knowing if you’re extremely sensitive to caffeine or avoiding it entirely for medical reasons.
Herbal Teas Are Naturally Caffeine-Free
Herbal infusions like rooibos, peppermint, chamomile, and hibiscus contain zero caffeine because they aren’t made from the tea plant at all. Rooibos, for example, comes from a South African shrub and is a popular swap for people who enjoy the ritual of tea without any stimulant effect.
The exception to watch for is yerba mate, which is an herbal infusion that does contain caffeine, typically 30 to 50 mg per cup. Guayusa is another naturally caffeinated herbal option. If a product is marketed as “herbal tea” and you’re avoiding caffeine, check the ingredient list for these.