An 8-ounce cup of green tea contains roughly 29 mg of caffeine, while the same size cup of brewed coffee delivers about 96 mg. That makes coffee roughly three times stronger in caffeine, cup for cup. But the real-world gap can be much wider or narrower depending on what you order, how you brew, and whether matcha is in the picture.
The Standard 8-Ounce Comparison
For a basic home-brewed cup, the numbers are straightforward. Green tea lands around 29 mg of caffeine per 8-ounce serving, while drip coffee comes in around 96 mg. That ratio holds fairly steady across most generic brands, though the exact number shifts depending on the tea leaves, bean variety, and brewing time. Coffee can range anywhere from 90 to 200 mg per cup depending on those variables, while green tea typically stays between 25 and 50 mg.
The FDA considers 400 mg of caffeine per day a safe amount for most healthy adults. That means you could drink roughly 4 cups of brewed coffee or about 13 cups of green tea before hitting that ceiling. For people who are caffeine-sensitive or trying to cut back, that difference gives green tea a lot more room.
What Coffee Shop Orders Actually Contain
Home brewing is one thing. Coffee shop sizes are another. A Starbucks grande (16 oz.) brewed coffee packs 315 to 390 mg of caffeine, which is nearly the entire daily recommended limit in a single cup. Even their short 8-ounce pour runs 155 to 195 mg. A Dunkin’ medium (14 oz.) comes in around 210 mg.
On the green tea side, the numbers stay modest. A Starbucks grande matcha latte contains about 65 mg of caffeine. A brewed Yogi Pure Green Tea bag delivers 58 mg. A 16-ounce bottle of Just Ice Tea Honey Green Tea has 50 mg. Even the higher end of commercial green tea products rarely crosses 70 mg, which is less than what you’d get from a single shot of espresso (about 75 mg at Starbucks).
So in a typical coffee shop scenario, the gap between green tea and coffee grows even larger than the standard 3:1 ratio. A grande brewed coffee can have five or six times the caffeine of a grande matcha latte.
Where Matcha Changes the Math
Matcha is ground whole tea leaves, so you consume the entire leaf rather than steeping and discarding it. That concentrates the caffeine. One gram of matcha powder contains about 25 mg of caffeine, and most servings use 2 grams, putting a standard matcha at around 50 mg per cup. A single shot of espresso (1 ounce) has about 63 mg.
That makes matcha the closest green tea gets to coffee territory. It still falls short of a full cup of drip coffee, but it’s no longer the mild option people sometimes assume. If you’re switching from coffee to matcha expecting a dramatic caffeine reduction, you’ll get one, but it’s more like cutting your intake in half rather than dropping to a fraction.
Why Green Tea Caffeine Feels Different
Many people report that green tea gives a calmer, more sustained energy boost compared to coffee, even when the caffeine amounts are similar. This isn’t just perception. Green tea contains an amino acid called L-theanine that directly interacts with caffeine in the brain. Animal studies have shown that L-theanine can inhibit some of the stimulatory effects of caffeine, smoothing out the jittery edge.
One particularly notable finding: L-theanine appears to lower cortisol levels, which is the body’s primary stress hormone. Caffeine on its own raises cortisol, especially under stress. The combination of L-theanine and caffeine in tea seems to produce an opposing effect, partially counteracting that stress response. Researchers studying the two compounds together found they have a “different pharmacological profile” than caffeine alone, improving focus and word recognition without the same degree of physical tension.
This is why someone drinking 50 mg of caffeine from green tea may feel alert but relaxed, while 50 mg from coffee might produce a sharper, more anxious buzz. The caffeine content tells you one part of the story. The L-theanine tells you the rest.
Does Roast Level Change Coffee’s Caffeine?
A common belief is that dark roast coffee has more caffeine because of its bolder flavor. The opposite is technically true, but barely. A 2018 study found that a sample of light roast brewed coffee contained about 60 mg of caffeine while the same amount of dark roast had 51 mg. That difference is small enough to vary between batches. As long as you measure coffee by weight rather than by volume (dark roast beans are slightly larger due to expansion during roasting), the caffeine content between light and dark roasts is essentially the same.
Brewing method and bean type matter more. A French press, pour-over, and drip machine will each extract caffeine differently. The variety of coffee bean (robusta beans have roughly twice the caffeine of arabica) has a bigger impact than any roast level.
How Steeping Time Affects Green Tea
With green tea, the biggest variable you control at home is steeping time. A quick 1-minute steep extracts less caffeine than leaving the bag in for 3 to 5 minutes. Water temperature also plays a role: green tea is typically brewed at 160 to 180°F, which is cooler than the boiling water used for coffee. That lower temperature extracts caffeine more slowly.
If you want to minimize caffeine from green tea, steep for a shorter time with cooler water. If you want to maximize it, use hotter water and let it sit longer. Either way, you’re unlikely to push a standard green tea bag past 50 mg per cup, which still keeps it well below the range of brewed coffee.
Practical Caffeine Counts at a Glance
- Brewed coffee (8 oz.): 96 mg average, range of 90 to 200 mg
- Starbucks grande brewed coffee (16 oz.): 315 to 390 mg
- Single espresso shot (1 oz.): 63 to 75 mg
- Brewed green tea (8 oz.): 29 mg average, range of 25 to 50 mg
- Matcha (2 g powder): about 50 mg
- Starbucks grande matcha latte (16 oz.): 65 mg
- Bottled green tea (16 oz.): 50 mg typical
For someone looking to reduce caffeine without eliminating it, green tea offers roughly a third of what coffee provides per cup, with a smoother energy curve thanks to L-theanine. For someone who wants the alertness of coffee in a tea format, matcha closes the gap but still comes in lower than a standard cup of drip.