A standard 8-ounce cup of brewed black tea contains about 48 mg of caffeine, while green tea has roughly 29 mg. That’s significantly less than an 8-ounce cup of coffee, which typically lands between 80 and 100 mg. But those numbers are just averages. The actual caffeine in your cup can range from under 15 mg to over 60 mg depending on the type of tea, the brand, and how you brew it.
Caffeine by Tea Type
All true teas come from the same plant, and the differences in caffeine largely come down to how the leaves are processed and which leaves are picked. Here’s what you can expect from an 8-ounce cup brewed for 3 to 5 minutes:
- Black tea: 25 to 50 mg, with most cups falling around 48 mg
- Green tea: 25 to 40 mg, averaging about 29 mg
- White tea: 25 to 47 mg (often similar to black tea, despite its mild flavor)
- Decaf black tea: 2 to 4 mg (not truly caffeine-free)
- Herbal tea: 0 mg (chamomile, peppermint, rooibos, and similar infusions contain no caffeine at all)
White tea surprises a lot of people. Because it tastes delicate, many assume it’s low in caffeine. Lab testing of a Chinese white tea found 47 mg per 6-ounce cup after five minutes of steeping, putting it right in line with a strong black tea. The mild taste comes from lower tannin levels, not lower caffeine.
How Brand Choice Changes Your Cup
The variation between brands is enormous. A study published in the Journal of Analytical Toxicology tested popular tea brands and found that a 6-ounce cup of Tazo Awake black tea delivered about 59 mg of caffeine after just one minute of steeping. Twinings English Breakfast, brewed for the same time, contained only 14 mg. After five minutes, Tazo Awake reached 61 mg while Twinings English Breakfast hit 25 mg. That’s more than a twofold difference between two black teas brewed identically.
Here are a few more brand comparisons at five minutes of steeping (per 6-ounce cup):
- Lipton Regular (black): 47 mg
- Stash Earl Grey (black): 47 mg
- Tazo Earl Grey (black): 59 mg
- Twinings Irish Breakfast (black): 30 mg
- Stash Premium Green: 36 mg
- Stash Darjeeling (black): 27 mg
If you’re trying to manage your caffeine intake, brand matters as much as tea type. Bottled and ready-to-drink teas also tend to be lower, around 26 mg per 8-ounce serving for black varieties, likely because they’re brewed in large batches with more dilution.
Steeping Time and Water Temperature
The way you brew your tea is one of the biggest levers you have over caffeine content. Hotter water and longer steep times both pull more caffeine out of the leaves, and the effect is dramatic.
Research measuring caffeine extraction from black tea at different temperatures found that steeping at room temperature (about 68°F) for four minutes produced only 10 mg per 8-ounce cup. The same tea steeped in boiling water for four minutes yielded 43 mg, more than four times as much. At boiling temperature, caffeine extraction peaked at around six minutes (roughly 47 mg) and then leveled off, so steeping longer than that doesn’t add much more caffeine.
If you want less caffeine from the same tea bag, steep for one to two minutes instead of five, or use water that’s below boiling. Green tea is traditionally brewed at lower temperatures (around 170°F), which is one reason it often delivers less caffeine than black tea in practice, even when the dry leaves contain similar amounts.
Why Caffeine Varies in the Leaves Themselves
Before brewing even enters the picture, the leaves themselves vary. Young leaves and leaf buds contain more caffeine than mature leaves. Tea harvested during monsoon season in major growing regions can contain up to 55 mg of caffeine per gram of dry leaf, compared to as low as 27 mg per gram from autumn harvests. The plant variety, altitude, and sunlight exposure all play a role too.
This is why you can’t reliably predict caffeine content from tea type alone. A high-grade green tea made from young buds might contain more caffeine than a lower-grade black tea made from mature leaves. The processing method (rolling, oxidation, firing) shifts the flavor, but it doesn’t determine caffeine content as much as the raw leaf material does.
Tea vs. Coffee
Cup for cup, tea delivers roughly half to one-third the caffeine of drip coffee. An 8-ounce coffee runs 80 to 100 mg on average, while most teas fall between 25 and 50 mg. For people looking to cut back on caffeine without eliminating it, switching from coffee to tea is a straightforward way to reduce intake by 50% or more per cup.
Tea also contains an amino acid called L-theanine that changes how caffeine feels. In a controlled trial, subjects who consumed both L-theanine and caffeine at doses similar to what you’d get from tea showed improved attention and focus compared to caffeine alone. L-theanine appears to promote a calmer, more sustained alertness rather than the sharp spike and crash some people experience with coffee. This is why many tea drinkers describe the energy from tea as “smoother.”
How Many Cups You Can Safely Drink
The FDA considers up to 400 mg of caffeine per day safe for most adults. At roughly 48 mg per cup of black tea, that works out to about 8 cups before reaching the limit. Green tea at 29 mg per cup gives you even more room. Most tea drinkers are well within safe territory even at three or four cups a day.
Decaf tea is not completely caffeine-free. A cup of decaf black tea still contains 2 to 4 mg, which is negligible for most people but worth knowing if you’re highly sensitive. True herbal teas (those not made from the tea plant) are the only completely caffeine-free option.