Mountain Dew vs Mello Yello: caffeine compared
Mountain Dew (12 oz) has 54 mg of caffeine, 3 mg more than Mello Yello (12 oz, 51 mg) — 1.1× as much per serving. Per fluid ounce, Mountain Dew is the stronger drink: 4.5 mg/oz versus 4.2 mg/oz.
| Mountain Dew | Mello Yello | |
|---|---|---|
| Serving | 12 oz | 12 oz |
| Caffeine per serving | 54 mg | 51 mg |
| Per fl oz | 4.5 mg | 4.2 mg |
| Share of 400 mg/day | 14% | 13% |
| Servings to reach 400 mg | 7.4 | 7.8 |
| Hours until under 50 mg | 0.6 h | 0.1 h |
| Last one for an 11 PM bedtime · standard (50 mg) | 10:27 PM | 10:51 PM |
| Last one for an 11 PM bedtime · sensitive (25 mg) | 5:27 PM | 5:51 PM |
| Share of the 200 mg pregnancy limit | 27% | 26% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, Mountain Dew or Mello Yello?
Mountain Dew (12 oz) has about 54 mg versus 51 mg in Mello Yello (12 oz): 3 mg more, or 1.1× as much.
Which is stronger per ounce, Mountain Dew or Mello Yello?
Mountain Dew: about 4.5 mg per fl oz versus 4.2 mg for Mello Yello. Serving size decides the total you actually drink.
How many Mello Yello servings equal one Mountain Dew?
About 1.1 servings of Mello Yello (12 oz) match the caffeine in one Mountain Dew (12 oz).
When should I stop drinking Mountain Dew or Mello Yello 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 Mello Yello by 10:51 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 — Mello Yello: Mello Yello 12 oz can (label as listed by Giant Food), checked 2026-10-13. Coca-Cola's brand page lists caffeine as an ingredient but not the amount.