Monster Energy vs Monster Ultra: caffeine compared
Monster Energy (16 oz) has 160 mg of caffeine, 10 mg more than Monster Ultra (16 oz, 150 mg) — 1.1× as much per serving. Per fluid ounce, Monster Energy is the stronger drink: 10.0 mg/oz versus 9.4 mg/oz.
| Monster Energy | Monster Ultra | |
|---|---|---|
| Serving | 16 oz | 16 oz |
| Caffeine per serving | 160 mg | 150 mg |
| Per fl oz | 10.0 mg | 9.4 mg |
| Share of 400 mg/day | 40% | 38% |
| Servings to reach 400 mg | 2.5 | 2.7 |
| Hours until under 50 mg | 8.4 h | 7.9 h |
| Last one for an 11 PM bedtime · standard (50 mg) | 2:37 PM | 3:05 PM |
| Last one for an 11 PM bedtime · sensitive (25 mg) | 9:37 AM | 10:05 AM |
| Share of the 200 mg pregnancy limit | 80% | 75% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, Monster Energy or Monster Ultra?
Monster Energy (16 oz) has about 160 mg versus 150 mg in Monster Ultra (16 oz): 10 mg more, or 1.1× as much.
Which is stronger per ounce, Monster Energy or Monster Ultra?
Monster Energy: about 10.0 mg per fl oz versus 9.4 mg for Monster Ultra. Serving size decides the total you actually drink.
How many Monster Ultra servings equal one Monster Energy?
About 1.1 servings of Monster Ultra (16 oz) match the caffeine in one Monster Energy (16 oz).
When should I stop drinking Monster Energy or Monster Ultra before bed?
For an 11 PM bedtime with a 50 mg limit and a 5-hour half-life: last Monster Energy by 2:37 PM, last Monster Ultra by 3:05 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 — Monster Energy: CSPI caffeine chart (Monster Energy Original, 16 oz), checked 2026-10-13.
Source — Monster Ultra: Monster Energy — Ultra (16 fl oz), checked 2026-10-13.