NOS vs Rockstar: caffeine compared
NOS and Rockstar carry the same caffeine per serving: 160 mg each. Per fluid ounce they are about the same: 10.0 mg/oz versus 10.0 mg/oz.
| NOS | Rockstar | |
|---|---|---|
| Serving | 16 oz | 16 oz |
| Caffeine per serving | 160 mg | 160 mg |
| Per fl oz | 10.0 mg | 10.0 mg |
| Share of 400 mg/day | 40% | 40% |
| Servings to reach 400 mg | 2.5 | 2.5 |
| Hours until under 50 mg | 8.4 h | 8.4 h |
| Last one for an 11 PM bedtime · standard (50 mg) | 2:37 PM | 2:37 PM |
| Last one for an 11 PM bedtime · sensitive (25 mg) | 9:37 AM | 9:37 AM |
| Share of the 200 mg pregnancy limit | 80% | 80% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, NOS or Rockstar?
Neither: both have about 160 mg per serving.
Which is stronger per ounce, NOS or Rockstar?
About the same: 10.0 mg per fl oz for NOS and 10.0 mg for Rockstar. The difference per can or cup comes from serving size.
When should I stop drinking NOS or Rockstar before bed?
For an 11 PM bedtime with a 50 mg limit and a 5-hour half-life: last NOS by 2:37 PM, last Rockstar by 2:37 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 — NOS: CSPI caffeine chart (NOS, 16 oz), checked 2026-10-13.
Source — Rockstar: CSPI caffeine chart (Rockstar Original, 16 oz), checked 2026-10-13.