How much caffeine is in oolong tea?
Oolong tea (237 ml) usually contains 4–29 mg of caffeine, about 17 mg on average.
Based on 2 g of dry leaf, 237 ml of water, about 5 min of steeping.
Key numbers
| Caffeine per cup | 4–29 mg |
|---|---|
| Volume | 237 ml |
| mg / 100 ml (average) | 7.2 |
| Compared with filter coffee (per cup) | 18% |
| Cups to reach 400 mg a day (adult) | more than 20 |
| Cups to reach 200 mg at once | 11 |
How caffeine changes with steeping
Longer steeping usually brings more caffeine. Figures for 2 g of tea.
| Steeping time | Caffeine per cup |
|---|---|
| 2 min | 3–19 mg |
| 3 min | 3–25 mg |
| 4 min | 4–27 mg |
| 5 min | 4–29 mg |
What about the evening?
After 6 hours roughly 1–16 mg of caffeine is still in the body (half-life 3–7 h). Sensitivity varies, so treat this as a guide, not a rule.
Frequently asked questions
How much caffeine is in oolong tea?
Oolong tea (237 ml) usually contains 4–29 mg of caffeine, about 17 mg on average. Based on 2 g of dry leaf, 237 ml of water, about 5 min of steeping.
Does oolong tea have more caffeine than filter coffee?
No, on average less: about 18% of the caffeine in a cup of filter coffee.
How many cups of oolong tea can I drink a day?
For adults EFSA gives up to 400 mg of caffeine a day from all sources. From this drink alone that is roughly more than 20 cups, if nothing else adds caffeine. In pregnancy the limit is 200 mg a day.
How does oolong tea compare with other teas and coffee?
See the "Caffeine in drinks" table: every drink is listed by caffeine per cup.
Try it
Sources and method
- Ayakdaş & Ağagündüz, Foods 2025;14(13):2313 (68 tea samples)
- EUFIC: EFSA opinion on the safety of caffeine (2015)
Data checked 2026-10-24. Ranges are shown because studies report different numbers. General information, not medical advice.