Red Bull vs Celsius: caffeine compared
Celsius (12 oz) has 200 mg of caffeine, 120 mg more than Red Bull (8.4 oz, 80 mg) — 2.5× as much per serving. Per fluid ounce, Celsius is the stronger drink: 16.7 mg/oz versus 9.5 mg/oz.
| Red Bull | Celsius | |
|---|---|---|
| Serving | 8.4 oz | 12 oz |
| Caffeine per serving | 80 mg | 200 mg |
| Per fl oz | 9.5 mg | 16.7 mg |
| Share of 400 mg/day | 20% | 50% |
| Servings to reach 400 mg | 5.0 | 2.0 |
| Hours until under 50 mg | 3.4 h | 10.0 h |
| Last one for an 11 PM bedtime · standard (50 mg) | 7:37 PM | 1:00 PM |
| Last one for an 11 PM bedtime · sensitive (25 mg) | 2:37 PM | 8:00 AM |
| Share of the 200 mg pregnancy limit | 40% | 100% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, Red Bull or Celsius?
Celsius (12 oz) has about 200 mg versus 80 mg in Red Bull (8.4 oz): 120 mg more, or 2.5× as much.
Which is stronger per ounce, Red Bull or Celsius?
Celsius: about 16.7 mg per fl oz versus 9.5 mg for Red Bull. Serving size decides the total you actually drink.
How many Red Bull servings equal one Celsius?
About 2.5 servings of Red Bull (8.4 oz) match the caffeine in one Celsius (12 oz).
When should I stop drinking Red Bull or Celsius before bed?
For an 11 PM bedtime with a 50 mg limit and a 5-hour half-life: last Red Bull by 7:37 PM, last Celsius by 1:00 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 — Red Bull: Red Bull — caffeine per can, checked 2026-10-13.
Source — Celsius: CSPI caffeine chart (Celsius, 12 oz), checked 2026-10-13.