Dr Pepper vs Pepsi: caffeine compared
Dr Pepper (12 oz) has 41 mg of caffeine, 3 mg more than Pepsi (12 oz, 38 mg) — 1.1× as much per serving. Per fluid ounce, Dr Pepper is the stronger drink: 3.4 mg/oz versus 3.2 mg/oz.
| Dr Pepper | Pepsi | |
|---|---|---|
| Serving | 12 oz | 12 oz |
| Caffeine per serving | 41 mg | 38 mg |
| Per fl oz | 3.4 mg | 3.2 mg |
| Share of 400 mg/day | 10% | 10% |
| Servings to reach 400 mg | 9.8 | 10.5 |
| Hours until under 50 mg | already under | already under |
| Last one for an 11 PM bedtime · standard (50 mg) | 11:00 PM | 11:00 PM |
| Last one for an 11 PM bedtime · sensitive (25 mg) | 7:26 PM | 7:59 PM |
| Share of the 200 mg pregnancy limit | 20% | 19% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, Dr Pepper or Pepsi?
Dr Pepper (12 oz) has about 41 mg versus 38 mg in Pepsi (12 oz): 3 mg more, or 1.1× as much.
Which is stronger per ounce, Dr Pepper or Pepsi?
Dr Pepper: about 3.4 mg per fl oz versus 3.2 mg for Pepsi. Serving size decides the total you actually drink.
How many Pepsi servings equal one Dr Pepper?
About 1.1 servings of Pepsi (12 oz) match the caffeine in one Dr Pepper (12 oz).
When should I stop drinking Dr Pepper or Pepsi before bed?
For an 11 PM bedtime with a 50 mg limit and a 5-hour half-life: last Dr Pepper by 11:00 PM, last Pepsi by 11:00 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 — Dr Pepper: CSPI caffeine chart (Dr Pepper, 12 oz), checked 2026-10-13.
Source — Pepsi: PepsiCo Product Facts — Pepsi 12 fl oz, checked 2026-10-13.