How Much Caffeine is in Tea? Complete Guide
A typical 240 ml cup of black tea contains 47 mg of caffeine.
- Black tea (240 ml): 47 mg; English Breakfast: 50 mg
- Green tea (240 ml): 28 mg70 mg
- Yerba mate (240 ml): 85 mg
- Herbal teas: 0 mg (caffeine-free).
- Green tea (240 ml): 28 mg70 mg
Caffeine content in common tea types
Below are dataset values measured per typical serving. Use the mg/100 ml column to scale for different cup sizes. Values come from standardized beverage analyses used by nutrition databases; for health guidance see FDA and Mayo Clinic.
| Tea | Serving | Caffeine (mg) | mg / 100 ml |
|---|---|---|---|
| Black tea | 240 ml | 47 mg | 19.6 mg/100ml |
| English Breakfast | 240 ml | 50 mg | 20.8 mg/100ml |
| Earl Grey | 240 ml | 47 mg | 19.6 mg/100ml |
| Green tea | 240 ml | 28 mg | 11.7 mg/100ml |
| White tea | 240 ml | 16 mg | 6.7 mg/100ml |
| Oolong | 240 ml | 37 mg | 15.4 mg/100ml |
| Matcha (1 tsp) | 240 ml | 70 mg | N/A |
| Chai latte | 240 ml | 50 mg | N/A |
| Yerba mate | 240 ml | 85 mg | 35.4 mg/100ml |
| Iced tea (bottled) | 355 ml | 45 mg | 12.7 mg/100ml |
| Herbal tea (caffeine-free) | 240 ml | 0 mg | 0 mg/100ml |
Why the numbers vary: what affects caffeine in a cup
Tea caffeine isn’t fixed by the leaf type alone. Key factors: leaf grade and age (younger buds concentrate more caffeine), leaf form (broken fannings release more quickly than whole leaves), water temperature, steep time, and tea-to-water ratio. Matcha is powdered whole-leaf, so a teaspoon gives you the whole-leaf caffeine (70 mg in the dataset) rather than an infusion’s fraction.
Measuring loose leaf vs tea bags
Tea bags often contain smaller leaf particles and more mass by volume, producing slightly higher extraction in a short steep than a similar weight of whole-leaf. Commercial bag blends (English Breakfast, Earl Grey) in the dataset are near 47–50 mg per 240 ml. Exact results require weighing the leaf and timing your steep — single gram changes matter.
How tea compares to coffee and energy drinks
Tea is generally lower in caffeine than brewed coffee and energy drinks. For comparison from the dataset: drip coffee (240 ml) ≈ 96 mg, pour-over 240 ml ≈ 145 mg, cold brew 240 ml ≈ 200 mg, and a single 30 ml espresso ≈ 63 mg. Yerba mate (85 mg per 240 ml) can overlap with weaker coffees, while matcha (70 mg) approaches espresso shot levels when consumed as a full cup.
| Beverage | Serving | Caffeine (mg) |
|---|---|---|
| Black tea | 240 ml | 47 mg |
| Green tea | 240 ml | 28 mg |
| Matcha (1 tsp) | 240 ml | 70 mg |
| Yerba mate | 240 ml | 85 mg |
| Drip coffee | 240 ml | 96 mg |
| Cold brew | 240 ml | 200 mg |
Caffeine decay: how much remains after hours
Population-average caffeine half-life is about 5.7 hours. Approximate retention fractions: after 3 h ≈ 69% remains, 6 h ≈ 48%, 9 h ≈ 33%, 12 h ≈ 23%. Here are concrete mg remaining from typical tea doses in the dataset.
| Tea (dose) | Dose (mg) | After 3 h | After 6 h | After 9 h | After 12 h |
|---|---|---|---|---|---|
| Black tea | 47 mg | ~32 mg | ~23 mg | ~16 mg | ~11 mg |
| Matcha (1 tsp) | 70 mg | ~48 mg | ~34 mg | ~23 mg | ~16 mg |
| Yerba mate | 85 mg | ~59 mg | ~41 mg | ~28 mg | ~20 mg |
| Green tea | 28 mg | ~19 mg | ~13 mg | ~9 mg | ~6 mg |
| White tea | 16 mg | ~11 mg | ~8 mg | ~5 mg | ~4 mg |
Health, safety, and timing
For healthy adults the FDA cites ~400 mg/day as a safe upper limit; the European Food Safety Authority and Mayo Clinic give similar guidance. Pregnant people are commonly advised to limit to about 200 mg/day. The American Academy of Pediatrics discourages caffeine for adolescents. Individual sensitivity, medications (CYP1A2 inhibitors), liver disease, and smoking (which speeds clearance) change effects substantially.
To protect sleep, avoid caffeine 6–8 hours before bed; because of the 5.7 h half-life some people need to stop earlier. If you track intake and timing, an app like CoffeeLog can calculate cumulative mg and predict residual caffeine at bedtime.
Practical tips to reduce or increase caffeine in tea
- Shorter steep (1–2 minutes) + lower water temperature reduces extraction.
- Use fewer grams of leaf per cup or re-steep leaves (later steeps have much less caffeine).
- Choose white or green teas for lower caffeine; choose yerba mate or matcha for higher caffeine without turning to coffee.
- Herbal tisane if you need zero caffeine.
Sources and next steps
Values above reflect composited beverage analyses used in nutrition databases and are consistent with guidance from USDA FoodData Central, FDA, EFSA, Mayo Clinic, and professional nutrition references. For an exact personal log, weigh servings and steep times and record them — CoffeeLog simplifies this process by converting common servings into mg and tracking timing against sleep.
Frequently asked questions
How much caffeine is in a cup of black tea?
A standard 240 ml cup of black tea contains about 47 mg of caffeine, per dataset values. Stronger bags or longer steeps can raise that number.
Does green tea have less caffeine than coffee?
Yes: green tea (240 ml) is about 28 mg, while drip coffee (240 ml) is about 96 mg in the dataset. Matcha (70 mg) and yerba mate (85 mg) are exceptions.
How does steeping time change caffeine?
Longer steep times and hotter water extract more caffeine; roughly, most caffeine transfers in the first few minutes, so reducing steep time lowers mg noticeably.
Is decaf tea caffeine-free?
Decaffeinated teas often contain small residual caffeine; herbal teas labeled caffeine-free contain 0 mg. Check lab-analyzed values for precise mg if needed.
How long does tea caffeine stay in your system?
Average half-life ≈ 5.7 hours: about 69% remains after 3 h, 48% after 6 h, 33% after 9 h and 23% after 12 h. Individual clearance varies.
Is tea safe during pregnancy?
Most guidelines advise limiting total caffeine to about 200 mg/day during pregnancy. Because tea contributes mg, consult your clinician to combine all sources (coffee, sodas, chocolate).