How much caffeine is in Green Tea (8oz cup)?
中文：绿茶（8 盎司）
Caffeine content
35 mg
Typical range: 25–50 mg
per 8 fl oz (237 ml)
About this drink
Brewed green tea has mild caffeine — about a third of a coffee cup. L-theanine, an amino acid present in tea, partially modulates caffeine's stimulant effect, giving green tea a 'calmer alert' feel.
Ingredients: Green tea leaves, hot water
When will it clear your system?
35 mg with L-theanine smoothing the curve. Three cups across the day is still under a single Grande Latte.
Based on caffeine's 5-hour half-life, a Green Tea (8oz cup) consumed at 2:00 PM drops below the sleep-safe threshold (~20 mg) by approximately 18:02 the same evening.
Where this fits in a daily limit
That's about 18% of the 200 mg pregnancy guideline and 9% of the 400 mg general adult daily limit — comfortably moderate.
See our pregnancy caffeine guide or half-life sleep math for the deep dive.
How it compares
| Drink | Caffeine |
|---|---|
Green Tea (8oz cup) Generic | 35 mg |
| Black Tea (8oz cup) Generic | 50 mg |
| Matcha Latte (Generic) Generic | 80 mg |
| Oolong Tea (8oz cup) Generic | 45 mg |
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Learn more about SipNoteFrequently asked questions
How much caffeine is in a Green Tea (8oz cup)?
A 8 fl oz (237 ml) Green Tea (8oz cup) contains approximately 35 mg of caffeine. Actual values may range from 25 to 50 mg depending on preparation and source variation.
Is Green Tea (8oz cup) safe during pregnancy?
The current ACOG and NHS guideline is under 200 mg of caffeine per day during pregnancy. A Green Tea (8oz cup) fits comfortably within that limit. Always consult your obstetrician for personalized advice.
When should I stop drinking Green Tea (8oz cup) for sleep?
Caffeine has a 5-hour half-life. To have under 20 mg circulating at bedtime (the typical sleep-safe threshold), stop drinking Green Tea (8oz cup) about 5 hours before sleep. 35 mg with L-theanine smoothing the curve. Three cups across the day is still under a single Grande Latte.
Green Tea (8oz cup) vs Black Tea (8oz cup) — which has more caffeine?
Green Tea (8oz cup) contains 35 mg per serving; Black Tea (8oz cup) contains 50 mg per 8 fl oz (237 ml). Black Tea (8oz cup) is the stronger of the two.
Does Green Tea (8oz cup) keep you awake?
35 mg is mild caffeine. Most people can drink Green Tea (8oz cup) in the afternoon without notable sleep impact.
Caffeine values shown are typical for the listed serving size. Actual content varies by preparation, brewing method, batch, and brand reformulation. Not medical advice — consult a healthcare provider for personalized guidance.