An 8-ounce cup of brewed black tea contains roughly 40 to 70 milligrams of caffeine, while the same size cup of brewed coffee delivers about 95 milligrams. That means coffee typically has about twice the caffeine of black tea, though the exact numbers shift depending on how you brew each drink, what variety you’re using, and how long you steep or extract.
The Basic Numbers Side by Side
For a standard 8-ounce serving, here’s what you’re looking at:
- Brewed black tea: 40–70 mg of caffeine
- Drip coffee: ~95 mg of caffeine
- Espresso (1-ounce shot): ~63 mg of caffeine
- Cold brew coffee: ~150 mg of caffeine
So if you’re switching from coffee to black tea to cut back on caffeine, you’re roughly halving your intake per cup. Cold brew is the strongest mainstream option at around 150 mg per 8 ounces, which is nearly four times what you’d get from the same volume of black tea.
Why the Range Is So Wide for Tea
Steeping time is the single biggest variable in how much caffeine ends up in your cup of tea. A study measuring Lipton black tea found that one minute of steeping produced only 17 mg of caffeine per 6 ounces of water. At three minutes, that jumped to 38 mg. By five minutes, it reached 47 mg. That’s nearly triple the caffeine just from letting the bag sit a few extra minutes.
Water temperature matters too, though in a somewhat counterintuitive way for tea. Research on caffeine extraction found that brewing tea between 45°C and 75°C (roughly 113°F to 167°F) preserved the most caffeine and beneficial compounds, while cranking the temperature up to 90°C (194°F) actually reduced caffeine levels along with other key chemicals. Most people brew tea with boiling or near-boiling water, which may actually yield less caffeine than a slightly cooler steep.
Why Coffee Varies Too
The species of coffee bean makes a dramatic difference. Arabica beans, the variety in most specialty coffee, contain about 1.2 to 1.5 percent caffeine by weight. Robusta beans pack roughly double that, at 2.2 to 2.7 percent. In practical terms, an 8-ounce cup brewed from Arabica beans delivers 95 to 140 mg of caffeine, while a Robusta cup can hit 150 to 200 mg.
For coffee, higher water temperatures extract more caffeine. The optimal extraction happens at 90°C to 100°C (194°F to 212°F) over about 15 minutes, which is why cold brew compensates by using a much longer extraction time, often 12 to 24 hours, resulting in that higher 150 mg concentration per serving.
Tea Feels Different for a Reason
Even at comparable doses, caffeine from tea and coffee doesn’t feel the same. Black tea contains an amino acid called L-theanine that changes how your brain responds to caffeine. L-theanine promotes alpha brain waves, the type associated with a state of alert relaxation. It also influences neurotransmitters linked to mood and focus.
The practical result is that tea tends to produce a calmer, more sustained alertness without the jittery spike and crash that coffee can trigger. When L-theanine and caffeine work together, studies suggest they improve attention and sustained concentration more effectively than caffeine alone. If you’ve ever noticed that tea makes you feel focused without feeling wired, that’s the L-theanine at work.
What About Decaf Versions?
Decaf isn’t truly caffeine-free for either drink, but the residual amounts are negligible. According to Mayo Clinic data, an 8-ounce cup of decaf brewed coffee contains about 2 mg of caffeine, and decaf black tea contains about the same. At those levels, you’d need to drink dozens of cups to approach the caffeine in a single regular serving.
How Many Cups Can You Have?
The FDA considers 400 mg of caffeine per day a safe amount for most healthy adults. That works out to roughly four 8-ounce cups of drip coffee or six to eight cups of black tea, depending on how strong you brew it. Individual tolerance varies based on body weight, medications, and sensitivity. Some people feel anxious or restless at half that amount, while others handle it easily.
For context, toxic effects like seizures can occur with rapid consumption of around 1,200 mg, which is why concentrated caffeine powders and supplements carry real risk. You’re unlikely to reach dangerous levels from brewed tea or coffee through normal drinking patterns, but stacking multiple sources throughout the day (coffee, tea, energy drinks, soda) adds up faster than most people realize.
Choosing Based on Your Goals
If you want maximum caffeine per cup, cold brew coffee is the clear winner at around 150 mg per 8 ounces. Standard drip coffee is the most common choice for a reliable 95 mg hit. If you’re looking to moderate your intake without going decaf, black tea offers a middle ground: enough caffeine to feel alert, paired with L-theanine for a smoother experience. You can also fine-tune your tea by adjusting steep time. A quick one-minute dip gives you a very light dose, while a full five-minute steep gets you closer to the upper end of tea’s range.
For people who are sensitive to caffeine but still want some, a short-steeped black tea can deliver as little as 25 to 30 mg per cup, roughly a quarter of what drip coffee provides. That flexibility is one of tea’s practical advantages: you can dial the caffeine up or down in a way that coffee doesn’t easily allow.