Coca-Cola Classic has more caffeine than Sunkist Zero Sugar: 34mg vs 19mg in the same 12 oz can. That is a 15mg gap, and since the cans match, the per-serving number is the whole story.
Coca-Cola Classic vs Sunkist Zero Sugar: the numbers
| Coca-Cola Classic | Sunkist Zero Sugar | |
|---|---|---|
| Caffeine per serving | 34mg per 12 oz can | 19mg per 12 oz can |
| Caffeine per fl oz | 2.8mg | 1.6mg |
| Servings to reach 400mg (FDA context) | 11.8 | 21.1 |
Sources: Coca-Cola Classic's figure is verified in our Coca-Cola Classic caffeine guide against Caffeine Informer (source); Sunkist Zero Sugar's figure is verified in our Sunkist Zero Sugar guide against Caffeine Informer (source).
Which one should you pick?
Pick Sunkist Zero Sugar when you want the lighter dose or a slower ramp, and Coca-Cola Classic when you actually need the bigger hit and know your tolerance. If you are stacking either with other caffeinated drinks through the day, run the math against the 400mg reference rather than guessing.
For context, the FDA cites 400mg of caffeine a day as an amount generally not associated with negative effects in healthy adults. Tolerance and health vary, so treat these numbers as information, not advice.
Related reading
- Coca-Cola Classic: the full caffeine guide
- Sunkist Zero Sugar: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
FAQ
Does Coca-Cola Classic or Sunkist Zero Sugar have more caffeine? Coca-Cola Classic: 34mg per 12 oz can versus 19mg per 12 oz can for Sunkist Zero Sugar.
Which is stronger per ounce? Coca-Cola Classic, at about 2.8mg per fluid ounce versus 1.6mg for Sunkist Zero Sugar.
Comparing caffeine? The caffeine comparison tool puts hundreds of drinks side by side, and the caffeine curfew calculator can check your cutoff time for tonight.