Green tea vs Coca-Cola: caffeine compared
Coca-Cola (12 oz) has 34 mg of caffeine, 6 mg more than Green tea (8 oz, 28 mg) — 1.2× as much per serving. Per fluid ounce, Green tea is the stronger drink: 3.5 mg/oz versus 2.8 mg/oz.
| Green tea | Coca-Cola | |
|---|---|---|
| Serving | 8 oz | 12 oz |
| Caffeine per serving | 28 mg | 34 mg |
| Per fl oz | 3.5 mg | 2.8 mg |
| Share of 400 mg/day | 7% | 8% |
| Servings to reach 400 mg | 14.3 | 11.8 |
| 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) | 10:11 PM | 8:47 PM |
| Share of the 200 mg pregnancy limit | 14% | 17% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, Green tea or Coca-Cola?
Coca-Cola (12 oz) has about 34 mg versus 28 mg in Green tea (8 oz): 6 mg more, or 1.2× as much.
Which is stronger per ounce, Green tea or Coca-Cola?
Green tea: about 3.5 mg per fl oz versus 2.8 mg for Coca-Cola. Serving size decides the total you actually drink.
How many Green tea servings equal one Coca-Cola?
About 1.2 servings of Green tea (8 oz) match the caffeine in one Coca-Cola (12 oz).
When should I stop drinking Green tea or Coca-Cola before bed?
For an 11 PM bedtime with a 50 mg limit and a 5-hour half-life: last Green tea by 11:00 PM, last Coca-Cola 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 — Green tea: USDA FoodData Central (SR Legacy 171917), checked 2026-10-13. 12 mg per 100 g × 237 g.
Source — Coca-Cola: Coca-Cola — What is caffeine? (FAQ), checked 2026-10-13.