Yes, tea contains caffeine. A standard 8-ounce cup of brewed black tea has about 48 mg of caffeine, while green tea has roughly 29 mg. That’s significantly less than brewed coffee, which averages 96 mg per cup, but it’s enough to notice, especially if you’re sensitive to caffeine or drinking several cups a day.
How much caffeine ends up in your cup depends on the type of tea, how hot your water is, and how long you let it steep. Here’s what to expect from each variety and how to control your intake.
Caffeine Levels by Tea Type
All “true” teas come from the same plant, Camellia sinensis. Black, green, white, and oolong are simply processed differently after harvest. That processing, along with which leaves are picked, determines how much caffeine winds up in your cup.
- Black tea: about 48 mg per 8-ounce cup
- Oolong tea: about 50 mg per cup
- Green tea: 29 to 50 mg per cup
- White tea: about 20 mg per cup
For comparison, an 8-ounce cup of brewed coffee contains about 96 mg of caffeine, and a single shot of espresso has around 63 mg. So even the strongest tea delivers roughly half the caffeine of a regular cup of coffee. Instant coffee falls somewhere in between at about 62 mg per cup.
Bottled and ready-to-drink teas tend to have less caffeine than freshly brewed. An 8-ounce serving of bottled black tea contains about 26 mg, nearly half the amount you’d get from brewing it yourself.
How Steeping Changes Your Caffeine
Two factors you control at home, water temperature and steeping time, have a dramatic effect on how much caffeine ends up in your cup. Hotter water extracts caffeine faster, and longer steeping pulls out more.
Research published by the American Chemical Society measured caffeine extraction at three temperatures and found striking differences. At boiling (100°C), a one-minute steep yielded about 25 mg per cup, and by six minutes that number climbed to roughly 47 mg. At 50°C (about the temperature of a lukewarm tap), the same tea only released 6 mg after one minute and 30 mg after six. At room temperature, the tea barely released any caffeine at all: just 1.4 mg after one minute and only 17 mg after a full eight minutes of steeping.
The practical takeaway: if you want less caffeine from the same tea, use cooler water and steep for a shorter time. If you want the full caffeine kick, use boiling water and let the bag sit for five to six minutes. After about six minutes at boiling, caffeine levels actually plateau and stop climbing.
Why Some Tea Leaves Have More Caffeine
The plant itself plays a role before brewing even begins. Young tea leaves and buds contain more caffeine than mature leaves. Caffeine concentration decreases as you move from the bud to the first leaf and then to the second leaf down the stem. Teas made from tips and young buds, like many white and premium green teas, start with more caffeine in the raw leaf. White tea still ends up lower in the cup because it’s typically brewed at cooler temperatures with shorter steeping times.
Growing conditions matter too. Tea plants grown in shade produce higher levels of caffeine compared to those grown in full sun. This is why certain Japanese green teas that are shade-grown before harvest can pack a surprising caffeine punch despite being “green.”
Herbal Tea Is a Different Story
Herbal teas, technically called tisanes, are not made from the Camellia sinensis plant. Chamomile, peppermint, rooibos, ginger, lavender, and elderberry blends are all naturally caffeine-free. They never contained caffeine to begin with, so there’s nothing to remove.
The one common exception is yerba mate, which does naturally contain caffeine despite being herbal. If you’re avoiding caffeine entirely, check the ingredients list for yerba mate, guayusa, or guarana, all of which are plant-based sources of caffeine that sometimes appear in herbal blends.
What About Decaf Tea?
Decaf tea is not completely caffeine-free. The decaffeination process removes most of the caffeine, but roughly 1 to 2 percent remains. According to Mayo Clinic data, an 8-ounce cup of decaf black tea contains about 2 mg of caffeine. That’s a tiny amount, unlikely to affect most people, but worth knowing if you’re extremely sensitive or cutting caffeine for medical reasons.
How Tea Fits Into Daily Caffeine Limits
The FDA considers up to 400 mg of caffeine per day safe for most healthy adults. At 48 mg per cup, you could drink about eight cups of black tea before reaching that threshold. With green tea at 29 mg, you’d have even more room.
Where people sometimes miscalculate is with large servings. A 16-ounce mug of black tea contains roughly double the caffeine of an 8-ounce cup, putting you closer to 100 mg, essentially the same as a cup of coffee. If you’re also drinking coffee, energy drinks, or eating chocolate throughout the day, those milligrams add up. Keeping a rough mental tally helps more than worrying about any single cup.