Green Tea vs Coffee: Caffeine Comparison

Green tea contains 20–50 mg of caffeine per 8 oz cup, compared to 80–200 mg in brewed coffee.

Use our science-backed comparator below to see exactly how your beverage stacks up — with min–max ranges, daily limit tracking, and cup equivalencies based on verified data from the FDA, EFSA, and peer-reviewed research.

Caffeine Comparator

Select a beverage, adjust the serving size, and see the results.

Includes sencha, dragonwell, gunpowder varieties

ml
Estimated Caffeine
20–50mg
Average: 35 mg
% of Daily Limit (400 mg)9%
1.0
cups of green tea
0.4
cups of coffee

Caffeine per Standard Serving — Visual Comparison

🍵 Green Tea
240 ml
35 mg
🍃 Matcha
240 ml
64 mg
☕ Black Tea
240 ml
55 mg
☕ Brewed Coffee
240 ml
95 mg
⚡ Espresso
30 ml
63 mg
Average caffeine shown per standard serving. Actual values vary by preparation method.

How This Comparison Works

Our comparator uses verified caffeine ranges (not single averages) drawn from the FDA, EFSA, USDA FoodData Central, Mayo Clinic, and published research. Each beverage has a scientifically established minimum and maximum caffeine content per standard serving:

BeverageStandard ServingCaffeine RangeAverage
🍵 Green Tea8 oz (240 ml)20–50 mg35 mg
🍃 Matcha2 g in 8 oz38–90 mg64 mg
☕ Black Tea8 oz (240 ml)40–70 mg55 mg
☕ Brewed Coffee8 oz (240 ml)80–200 mg95 mg
⚡ Espresso1 shot (30 ml)63–80 mg63 mg

When you adjust the serving size, caffeine is scaled linearly from the per-240 ml base values. You can also enter a known custom value to override the estimate and see how it compares.

Why Caffeine Levels Vary

Plant & Growing Factors

  • Variety: Camellia sinensis var. sinensis (tea) vs. Coffea arabica vs. robusta
  • Shade growing: Increases caffeine up to 2× (gyokuro, matcha)
  • Harvest time: First harvest (spring) leaves have more caffeine
  • Altitude: Higher altitude can increase caffeine concentration

Preparation Factors

  • Water temperature: Hotter water extracts more caffeine
  • Brewing time: Longer steep = more caffeine extraction
  • Grind size: Finer coffee grounds increase extraction rate
  • Leaf-to-water ratio: More tea leaves = more caffeine per cup

Frequently Asked Questions

How much caffeine does green tea have compared to coffee?▼
An 8 oz cup of green tea contains 20–50 mg of caffeine (average 35 mg), while the same amount of brewed coffee contains 80–200 mg (average 95 mg). Green tea has roughly one-third the caffeine of coffee per serving.
Does matcha have more caffeine than coffee?▼
A standard 2 g matcha serving contains 38–90 mg of caffeine (average 64 mg), which is less than a typical 8 oz coffee (95 mg average). However, matcha contains L-theanine, which modulates caffeine for a smoother, more sustained energy release.
What is the safe daily caffeine limit?▼
Both the FDA and EFSA consider up to 400 mg of caffeine per day safe for most healthy adults. This is equivalent to roughly 4 cups of brewed coffee, or 8–11 cups of green tea. Pregnant and breastfeeding women are advised to stay under 200 mg per day.
Why does caffeine content vary so much between servings?▼
Caffeine content varies based on plant variety, growing conditions (shade-grown teas have more caffeine), processing method, brewing time and temperature, and the leaf-to-water ratio.
Is green tea a healthier source of caffeine than coffee?▼
Green tea provides caffeine alongside L-theanine and catechins (especially EGCG). L-theanine promotes calm focus and may reduce caffeine jitters. Coffee provides its own antioxidants (chlorogenic acids). Both can be part of a healthy diet; the choice depends on individual tolerance and preferences.

Sources & References

All caffeine values are based on peer-reviewed research and authoritative regulatory data:

  • FDA — Spilling the Beans: How Much Caffeine is Too Much? fda.gov
  • EFSA (2015) — Scientific Opinion on the Safety of Caffeine. efsa.europa.eu
  • Mayo Clinic — Caffeine Content for Coffee, Tea, Soda and More. mayoclinic.org
  • USDA FoodData Central — Caffeine content database. fdc.nal.usda.gov
  • Heckman MA, et al. (2010) — Caffeine in Foods: A Comprehensive Review. PubMed PMID: 20492310
  • Healthline — How Much Caffeine Is in Green Tea? healthline.com

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