An 8-ounce cup of brewed coffee contains 95–165 mg of caffeine, while an 8-ounce cup of brewed black tea contains 25–50 mg. That makes coffee roughly 3 to 6 times more caffeinated than tea by volume. But the comparison falls apart the moment you look at actual drinking behavior — because nobody drinks 8 ounces of coffee and stops, and nobody drinks only one cup of tea.
Sam drinks tea the way I drink water. She steeps a bag of English Breakfast at 7 AM, refills the mug with hot water twice, and then switches to Earl Grey at 10 AM. By noon, she has consumed three tea bags and roughly 120 mg of caffeine — spread across 24 ounces of fluid. I drink one 12-ounce pour-over at 8 AM and hit 180 mg immediately. Her caffeine is a slow drip. Mine is a bolus injection. The total daily dose ends up closer than the per-cup numbers suggest.
The chemistry behind the difference is straightforward. Coffee beans (Coffea arabica and Coffea canephora) contain 1.2–2.2% caffeine by dry weight. Tea leaves (Camellia sinensis) contain 2.5–4% caffeine by dry weight — actually higher than coffee. But you use far less tea leaf per cup. A standard coffee dose is 15–20 grams of ground coffee per 12 ounces of water. A standard tea dose is 2–3 grams of leaf per 8 ounces of water. The extraction efficiency is also different: hot water pulls caffeine from coffee grounds more aggressively than it does from whole tea leaves, but the starting mass difference overwhelms everything else.
Here is the real data, measured by serving size and brew method:
| Beverage | Serving Size | Caffeine (mg) | mg per oz | Typical Daily Consumption |
|----------|-------------|--------------|-----------|--------------------------|
| Drip coffee | 8 oz | 95–165 | 12–21 | 2–3 cups (190–495 mg) |
| Espresso (single) | 1 oz | 60–75 | 60–75 | 1–2 shots (60–150 mg) |
| Cold brew | 12 oz | 150–240 | 12.5–20 | 1 cup (150–240 mg) |
| Black tea | 8 oz | 25–50 | 3–6 | 2–4 cups (50–200 mg) |
| Green tea | 8 oz | 20–35 | 2.5–4 | 2–3 cups (40–105 mg) |
| Matcha | 8 oz | 60–70 | 7.5–9 | 1–2 cups (60–140 mg) |
| Yerba mate | 8 oz | 80–85 | 10–11 | 1–2 cups (80–170 mg) |
| Oolong tea | 8 oz | 30–50 | 3.5–6 | 1–2 cups (30–100 mg) |
The matcha number surprises people. Matcha is powdered whole leaf, so you are consuming the entire leaf rather than an infusion. A single teaspoon of ceremonial-grade matcha — about 2 grams — contains 60–70 mg of caffeine. That is more than a shot of espresso, delivered in a gentle, grassy beverage that feels nothing like coffee. I have seen people switch to matcha thinking they are reducing their caffeine intake, only to discover they are drinking the equivalent of two espressos before lunch.
Yerba mate occupies a strange middle ground. It is not coffee, and it is not tea — it is Ilex paraguariensis, a South American holly. But its caffeine content per ounce sits between black tea and drip coffee. The traditional preparation involves repeatedly refilling the gourd with hot water, which means one load of leaf can produce 20+ ounces of beverage over several hours. The total caffeine yield from a single gourd filling can reach 150–200 mg. I tried it once at a cafe in Capitol Hill. By the third refill, I felt the sympathetic activation — elevated heart rate, slight tremor, that familiar coffee feeling. It is not mild just because it is not coffee.
What most people miss is the L-theanine factor. Tea — especially green tea and matcha — contains L-theanine, an amino acid that crosses the blood-brain barrier and promotes alpha-wave activity. L-theanine modulates caffeine's effects, smoothing the peak and reducing the jitteriness. This is why Sam can drink 120 mg of caffeine from tea and feel calm, while 120 mg from coffee makes me anxious. The drugs are the same — caffeine is caffeine — but the delivery vehicle changes the subjective experience. Coffee is pure caffeine with no mitigating compounds. Tea is caffeine bundled with a natural anxiolytic.
I tested this on myself in a controlled n=1 experiment. For two weeks, I consumed exactly 150 mg of caffeine per day — one week from coffee, one week from matcha. Same dose. Same timing. I logged heart rate variability, subjective anxiety scores, and sleep quality. The coffee week produced higher morning peaks in heart rate and lower sleep efficiency. The matcha week was smoother. The data was not dramatic — the difference in sleep efficiency was only 8% — but it was consistent. The L-theanine matters. It does not change the pharmacokinetics of caffeine, but it changes the pharmacodynamics, how the drug feels.
If you are trying to reduce your caffeine intake, switching from coffee to tea is a reasonable strategy, but you need to be honest about the math. Two cups of black tea is not "cutting back" if you were only drinking one cup of coffee. You need to compare total milligrams, not cups. A daily caffeine limit calculator can help you model the switch accurately, accounting for the different serving sizes and re-steeping habits that tea drinkers develop.
The other variable is brewing time. Caffeine extraction from tea leaves follows a diffusion curve — 50% of available caffeine is extracted in the first 30 seconds, 80% by 2 minutes, and 95% by 5 minutes. A tea bag steeped for 30 seconds contains roughly half the caffeine of the same bag steeped for 3 minutes. I know people who "lightly steep" their tea to reduce caffeine, but the reduction is modest and unpredictable. If you want less caffeine, drink less tea or switch to a lower-caffeine variety. Do not rely on brew time as a precision tool.
Coffee, by contrast, extracts caffeine almost completely during normal brewing. A drip machine running for 4–6 minutes pulls 95%+ of available caffeine from the grounds. Espresso, despite the short 25–30 second contact time, uses pressure and fine grind to achieve similar extraction efficiency. You cannot "lightly brew" coffee to meaningfully reduce caffeine. Decaf is the only option, and as I have written elsewhere, decaf is not zero.
So which has more caffeine — coffee or tea? Coffee, by a factor of three to six per ounce. But tea drinkers often drink more ounces, and the total daily dose can converge. The real question is not which beverage has more caffeine. It is which beverage delivers caffeine in a way that matches your metabolism, your sensitivity, and your sleep schedule. For me, that is neither. It is a single morning cup of coffee, measured precisely, consumed before 9 AM, and logged in my tracker. For Sam, it is three cups of tea spread across the morning, each one a gentle wave rather than a tsunami.
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### Frequently Asked Questions
#### Does coffee or tea have more caffeine?
Coffee has significantly more caffeine per ounce — 12–21 mg per ounce compared to tea's 3–6 mg per ounce. However, tea drinkers often consume larger volumes, so total daily caffeine intake can be similar between heavy tea drinkers and moderate coffee drinkers.
#### Is matcha higher in caffeine than coffee?
Per ounce, no — matcha contains about 7.5–9 mg per ounce, while coffee contains 12–21 mg per ounce. But matcha is consumed in smaller volumes (6–8 oz), so a single serving of matcha (60–70 mg) can equal or exceed a single espresso shot (60–75 mg).
#### Does steeping tea longer increase caffeine?
Yes, but with diminishing returns. About 50% of tea's caffeine extracts in the first 30 seconds, 80% by 2 minutes, and 95% by 5 minutes. Steeping beyond 5 minutes adds minimal caffeine but increases bitterness from tannins.
#### Can I reduce caffeine by switching from coffee to green tea?
Only if you reduce total milligrams. One cup of coffee (150 mg) equals roughly 4–5 cups of green tea. If you drink 2 cups of green tea, you have reduced your intake. If you drink 6 cups, you have not.
#### Why does tea feel less jittery than coffee?
Tea contains L-theanine, an amino acid that promotes alpha brain waves and partially antagonizes caffeine's stimulant effects. This creates a smoother, more sustained alertness compared to coffee's sharper peak and crash.
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Alex Morgan, from the loft where Sam is steeping her third bag of Earl Grey and I am staring at my single cup like it owes me money.
Caffeine is a tool, not a lifestyle. Measure it.
