How Much Caffeine Is in Green Tea?
Green tea contains 30–50 mg of caffeine per 8 oz (240ml) cup.
However, the exact amount varies significantly based on:
- Tea type (matcha, sencha, gyokuro)
- Brewing time (1–5+ minutes)
- Water temperature (60–100°C)
- Serving size and leaf amount
Use our calculator below to get a personalized estimate for your specific brew.
Green Tea Caffeine Calculator
Log your caffeine intake, compare tea types, and track your daily consumption
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Tea Details
Base caffeine: 20mg per gram · EGCG: 45mg/g · L-Theanine: 15mg/g
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Caffeine Content
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Tea Enthusiast — 400mg/day chosen limit
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Caffeine Comparison
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Brewing & Caffeine Tips
- • Cold brewing extracts less caffeine (60-70%)
- • First steep extracts 60–70% of total caffeine
- • Consider timing tea ~6h before bedtime
- • Average caffeine half-life: ~5.7h
- • Hojicha & Genmaicha are naturally lower in caffeine
How This Caffeine Calculator Works
Our calculator uses research-backed formulas to estimate caffeine content based on multiple extraction factors. Here's the science behind the numbers:
Base Caffeine by Tea Type
Each green tea variety has a different caffeine concentration per gram of dry leaf. Shade-grown teas like Gyokuro have higher caffeine (32–50 mg/g) because shade increases caffeine production as a natural UV defense. Roasted teas like Hojicha have lower caffeine (4–8 mg/g) because roasting sublimes and degrades caffeine.
Brewing Time Extraction Curve
| Steep Time | % Caffeine Extracted | Notes |
|---|---|---|
| 1 minute | ~30% | Light, delicate brew |
| 3 minutes | ~60% | Standard brew |
| 5 minutes | ~80% | Strong brew |
| 6+ minutes | 85–90% | Maximum extraction (may be bitter) |
Temperature Impact
Higher water temperatures extract more caffeine. At 70°C (158°F), extraction is about 60% efficient. At 100°C (212°F), extraction reaches nearly 100%. Most green teas are best brewed at 70–80°C to balance flavor and moderate caffeine.
Multi-Steep Caffeine Decay
When you re-steep tea leaves, each subsequent infusion contains less caffeine. The first steep extracts 60–70% of total caffeine. The second steep extracts 20–25%. By the third or fourth steep, only 8–15% remains.
Matcha vs. Brewed Green Tea: Caffeine Comparison
Matcha
- Caffeine per gram: 19–45 mg
- Standard serving (2g): 38–90 mg
- Why higher? You consume the entire leaf, not just an infusion
- L-Theanine: Higher (~25–50 mg per serving), promotes calm alertness
Brewed Green Tea
- Caffeine per 8oz cup: 30–50 mg
- Standard serving: 30–50 mg
- Why lower? Only water-soluble compounds are extracted
- L-Theanine: Moderate (~10–20 mg per cup)
Key insight: Matcha provides a more sustained energy boost due to higher L-theanine, which modulates caffeine absorption and reduces jitters.
Green Tea vs. Coffee & Other Drinks
| Beverage (8 oz / 240ml) | Caffeine (mg) | % of Green Tea |
|---|---|---|
| Green Tea | 30–50 | 100% |
| ☕ Brewed Coffee | 95–200 | 240–500% |
| 🍵 Black Tea | 40–70 | 100–175% |
| ⚡ Energy Drink | 70–100 | 175–250% |
| 🥤 Cola (12 oz) | 30–40 | 75–100% |
| 🍵 Matcha (2g) | 38–90 | 95–225% |
Source: USDA FoodData Central, Healthline, PubMed (Heckman et al., 2010)
Daily Caffeine Intake Reference
A commonly referenced daily caffeine guideline for adults is up to 400 mg (per FDA). In terms of green tea, that's approximately:
- 8–13 cups of green tea (at 30–50 mg each)
- 4–5 cups of brewed coffee
- 4–5 servings of matcha
📝 Things to Keep in Mind
- Individual tolerance varies: Some people are naturally more sensitive to caffeine than others
- Timing matters: Caffeine consumed close to bedtime may affect how quickly you fall asleep
- Multiple sources add up: Remember to count caffeine from coffee, energy drinks, and chocolate too
- Listen to your body: Adjust your intake based on how you personally feel
Caffeine Half-Life
Caffeine has an average half-life of about 5 hours, meaning half the caffeine you consume will still be in your system 5 hours later. Many people find it helpful to finish their last caffeinated drink at least 6 hours before bedtime.
This tool is for informational and personal logging purposes only. It is not a substitute for professional advice.
Frequently Asked Questions
How much caffeine is in green tea?▼
Does green tea have more caffeine than coffee?▼
How much caffeine is in matcha vs regular green tea?▼
How does brewing time affect caffeine in green tea?▼
How many cups of green tea can I have per day?▼
Does decaf green tea have caffeine?▼
Sources & References
All caffeine values and scientific claims are based on peer-reviewed research and authoritative sources:
- Heckman MA, et al. (2010) — Caffeine in Foods: A Comprehensive Review. PubMed PMID: 20492310
- Cabrera C, et al. (2006) — Beneficial Effects of Green Tea: A Literature Review. PubMed PMID: 20370896
- FDA — Spilling the Beans: How Much Caffeine is Too Much? fda.gov
- USDA FoodData Central — Caffeine content database. fdc.nal.usda.gov
- Healthline — How Much Caffeine Is in Green Tea? healthline.com