Mountain Dew vs Red Bull: caffeine compared
Red Bull (8.4 oz) has 80 mg of caffeine, 26 mg more than Mountain Dew (12 oz, 54 mg) — 1.5× as much per serving. Per fluid ounce, Red Bull is the stronger drink: 9.5 mg/oz versus 4.5 mg/oz.
| Mountain Dew | Red Bull | |
|---|---|---|
| Serving | 12 oz | 8.4 oz |
| Caffeine per serving | 54 mg | 80 mg |
| Per fl oz | 4.5 mg | 9.5 mg |
| Share of 400 mg/day | 14% | 20% |
| Servings to reach 400 mg | 7.4 | 5.0 |
| Hours until under 50 mg | 0.6 h | 3.4 h |
| Last one for an 11 PM bedtime · standard (50 mg) | 10:27 PM | 7:37 PM |
| Last one for an 11 PM bedtime · sensitive (25 mg) | 5:27 PM | 2:37 PM |
| Share of the 200 mg pregnancy limit | 27% | 40% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, Mountain Dew or Red Bull?
Red Bull (8.4 oz) has about 80 mg versus 54 mg in Mountain Dew (12 oz): 26 mg more, or 1.5× as much.
Which is stronger per ounce, Mountain Dew or Red Bull?
Red Bull: about 9.5 mg per fl oz versus 4.5 mg for Mountain Dew. Serving size decides the total you actually drink.
How many Mountain Dew servings equal one Red Bull?
About 1.5 servings of Mountain Dew (12 oz) match the caffeine in one Red Bull (8.4 oz).
When should I stop drinking Mountain Dew or Red Bull before bed?
For an 11 PM bedtime with a 50 mg limit and a 5-hour half-life: last Mountain Dew by 10:27 PM, last Red Bull by 7:37 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 — Mountain Dew: PepsiCo Product Facts — Mountain Dew, checked 2026-10-13. 54 mg per 12 fl oz serving.
Source — Red Bull: Red Bull — caffeine per can, checked 2026-10-13.