Coffee has significantly more caffeine than tea per cup. An 8-ounce cup of brewed coffee delivers roughly 80 to 100 mg of caffeine, while the same size cup of black tea contains about 47 mg. That gap widens even further when you factor in real-world serving sizes, since most people drink coffee in 12- or 16-ounce portions.
Why Coffee Wins Despite Having Less Caffeine by Weight
Here’s a fact that surprises most people: tea leaves actually contain more caffeine than coffee beans on a pound-for-pound basis. Dry tea leaves are about 4% caffeine, while coffee beans range from 0.9% to 2.6%. So why does coffee end up being the stronger drink?
Two things flip the equation. First, coffee is brewed with near-boiling or boiling water and extracted under pressure or prolonged contact, which pulls far more caffeine out of the grounds. Second, you use a lot more coffee per cup than you do tea. A typical coffee recipe calls for 10 to 15 grams of grounds per 8-ounce cup, while a single tea bag holds about 2 grams of leaves. More raw material plus more aggressive extraction equals a much more caffeinated drink.
Caffeine Across Tea Types
Not all teas are created equal. The variety, processing method, and how you brew it all shift the caffeine content considerably.
- Black tea: 40 to 70 mg per 8-ounce cup, with a USDA average around 47 mg
- Green tea: 20 to 45 mg, averaging about 28 mg
- White tea: 15 to 40 mg
- Matcha: 60 to 70 mg per serving, because you consume the entire ground leaf rather than steeping and discarding it
Matcha is the outlier. Since you’re whisking powdered tea directly into water and drinking the whole leaf, none of the caffeine gets left behind. A cup of matcha lands in the same ballpark as a weak cup of coffee.
How Steeping Changes Everything
The amount of caffeine in your tea depends heavily on water temperature and steeping time. Research published by the American Chemical Society measured caffeine extraction from tea at different temperatures and found dramatic differences. At room temperature (about 68°F), steeping for 4 minutes yielded only 10 mg of caffeine per 8-ounce cup. The same tea steeped at boiling temperature for 4 minutes produced 43 mg, more than four times as much.
Caffeine extraction at high temperatures peaks around the 6-minute mark, hitting roughly 47 mg per cup in the study, then plateaus. Steeping longer than that doesn’t add meaningfully more caffeine. At lower temperatures, caffeine keeps climbing slowly even after 8 minutes but never catches up to a hot brew. So if you want less caffeine from your tea, steep it cooler and shorter. If you want more, use boiling water and give it a full 5 to 6 minutes.
Caffeine Across Coffee Types
Coffee brewing methods create their own wide range. A single shot of espresso packs about 60 to 65 mg of caffeine into just one ounce, making it by far the most concentrated form. But because the serving size is so small, a single espresso actually contains less total caffeine than a standard drip coffee.
Cold brew sits at the other end of the spectrum. The long extraction time (usually 12 to 24 hours) pulls out a lot of caffeine. A typical 16-ounce cold brew averages 180 to 200 mg, or about 12 to 13 mg per ounce. That’s less concentrated than espresso ounce for ounce, but you’re drinking 16 times the volume.
The type of bean matters too. Robusta beans contain 2.2% to 2.7% caffeine, while Arabica beans come in at 1.2% to 1.5%. Most specialty coffee shops use Arabica for its smoother flavor, but cheaper blends and instant coffees often include Robusta, which can push the caffeine content noticeably higher.
Real-World Serving Sizes
Lab comparisons use a standard 8-ounce cup, but almost nobody orders 8 ounces of coffee at a café. A Starbucks grande is 16 ounces and contains 315 to 390 mg of caffeine. Even a 12-ounce tall runs 235 to 290 mg. A large Dunkin’ coffee (20 ounces) delivers about 270 mg. These are all from a single drink.
Tea servings tend to stay closer to the 8-ounce standard, especially when brewed at home with one tea bag. Even if you use a large mug (12 ounces), you’re still typically steeping the same single bag, so the caffeine doesn’t scale up the way coffee does when you simply pour more from a full pot. This means the practical gap between coffee and tea is often larger than the per-cup comparison suggests. A single grande coffee from Starbucks can contain as much caffeine as six to eight cups of green tea.
How Much Caffeine Is Safe
The FDA considers 400 mg of caffeine per day safe for most healthy adults. That’s roughly two to three 12-ounce cups of brewed coffee, or about eight cups of black tea. Most tea drinkers stay well within that limit without thinking about it. Coffee drinkers can hit the ceiling faster, especially with large servings or concentrated styles like cold brew.
If you’re sensitive to caffeine or looking to cut back, switching from coffee to tea is one of the simplest ways to reduce your intake while still getting a mild boost. A cup of green tea gives you about a quarter of the caffeine in a cup of coffee, enough to feel alert without the jitters that stronger doses can cause.