Kombucha vs Green tea: caffeine compared
Green tea (8 oz) has 28 mg of caffeine, 3 mg more than Kombucha (16 oz, 25 mg) — 1.1× as much per serving. Per fluid ounce, Green tea is the stronger drink: 3.5 mg/oz versus 1.6 mg/oz.
| Kombucha | Green tea | |
|---|---|---|
| Serving | 16 oz | 8 oz |
| Caffeine per serving | 25 mg | 28 mg |
| Per fl oz | 1.6 mg | 3.5 mg |
| Share of 400 mg/day | 6% | 7% |
| Servings to reach 400 mg | 16.0 | 14.3 |
| Hours until under 50 mg | already under | already under |
| Last one for an 11 PM bedtime · standard (50 mg) | 11:00 PM | 11:00 PM |
| Last one for an 11 PM bedtime · sensitive (25 mg) | 11:00 PM | 10:11 PM |
| Share of the 200 mg pregnancy limit | 12% | 14% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, Kombucha or Green tea?
Green tea (8 oz) has about 28 mg versus 25 mg in Kombucha (16 oz): 3 mg more, or 1.1× as much.
Which is stronger per ounce, Kombucha or Green tea?
Green tea: about 3.5 mg per fl oz versus 1.6 mg for Kombucha. Serving size decides the total you actually drink.
How many Kombucha servings equal one Green tea?
About 1.1 servings of Kombucha (16 oz) match the caffeine in one Green tea (8 oz).
When should I stop drinking Kombucha or Green tea before bed?
For an 11 PM bedtime with a 50 mg limit and a 5-hour half-life: last Kombucha by 11:00 PM, last Green tea by 11:00 PM. Half-life varies from about 1.5 to 9.5 hours between people.
Method
Caffeine per labeled serving, from the same drink table every calculator here uses (FDA/USDA reference amounts and manufacturer labels; see caffeine content of every drink). Brewed drinks vary batch to batch, so read these as typical values. Decay uses a 5-hour average half-life with a 45-minute absorption ramp; cutoff = bedtime − 5 h × log₂(dose ÷ limit). Percentages use the FDA's 400 mg/day figure for healthy adults and the 200 mg/day limit ACOG gives for pregnancy.
Source — Kombucha: CSPI caffeine chart (GT's Synergy Kombucha, 16 oz), checked 2026-10-13. 16–28 mg per 16 oz; 25 mg sits inside that range. Published range 16–28 mg.
Source — Green tea: USDA FoodData Central (SR Legacy 171917), checked 2026-10-13. 12 mg per 100 g × 237 g.