The short answer: coffee has roughly double the caffeine
An 8 oz (240 ml) cup of brewed coffee contains about 95 mg of caffeine (range: 80–120 mg depending on beans and brew method). The same size cup of green tea contains about 25–50 mg (range varies by leaf grade and steep time). Matcha, because you consume the whole leaf, lands higher: roughly 60–70 mg per serving.
So by the numbers, coffee delivers roughly twice the caffeine per cup. But many people find that green tea gives a smoother, longer-lasting energy boost without the jitters — and that’s down to a compound called L-theanine.
The numbers side by side
Here are typical caffeine amounts for a standard 8 oz serving:
• Drip coffee: 80–120 mg (average ≈95 mg).
• Espresso (1 shot, 1 oz): ≈63 mg.
• Cold brew (8 oz): 100–200 mg (often the highest on the menu).
• Green tea (steeped 3 min): 25–50 mg.
• Matcha (1 tsp whisked): 60–70 mg.
• Black tea (steeped 3–5 min): 40–70 mg.
Steep time matters for tea: a 1-minute steep may extract half the caffeine of a 5-minute steep. Coffee is less sensitive because near-boiling water and finer grounds extract caffeine quickly. Track your total intake with the Caffeine Calculator.
Why the effect feels different: L-theanine
Green tea contains L-theanine, an amino acid that promotes calm alertness. Research published in *Nutritional Neuroscience* (2008) found that L-theanine modulates the stimulating effects of caffeine, reducing jitteriness and improving focused attention.
Coffee does not contain meaningful L-theanine. Its caffeine hits faster and harder — peak blood levels arrive in about 30–60 minutes. The combination of high caffeine and no L-theanine is why coffee is more likely to cause jitters, a racing heart, or an energy crash 4–6 hours later. See how long caffeine lasts for the timeline.
When each makes sense
• Choose coffee when you need a fast, strong energy boost — before a morning workout, to kick off a workday, or when you need peak focus in 30 minutes.
• Choose green tea when you want gentle, sustained alertness without the crash — afternoons, after lunch, or if caffeine makes you anxious.
• Choose matcha for something in between: more caffeine than green tea, plus the full L-theanine dose from the powdered leaf.
Your caffeine cutoff time still applies to both — caffeine is caffeine regardless of the source.
Switching from coffee to green tea
If you want to reduce caffeine without going cold turkey, swapping one cup of coffee for green tea drops your intake by about 50–70 mg per swap. A common strategy:
• Week 1: Replace your afternoon coffee with green tea.
• Week 2: Replace your second morning coffee with matcha.
• Week 3: You’re down to one coffee plus 1–2 teas — roughly half your original caffeine.
Expect mild withdrawal headaches for 1–3 days when you cut back. They pass. Use the Caffeine Half-Life Calculator to plan your timing.