Starbucks London Fog has more caffeine than Sunkist Zero Sugar on both counts: 40mg per 16 oz grande (40mg at every size) against 19mg per 12 oz can, and about 2mg per fluid ounce against 2. The serving sizes differ, so the table below shows both ways of counting.
These are different categories of drink, which changes how the caffeine arrives. Energy drinks and sodas list an exact number because caffeine is a measured additive; brewed drinks vary with the beans and the brew, so their figures are compiled averages. The numbers here are the standard published values for each.
Starbucks London Fog vs Sunkist Zero Sugar: the numbers
| Starbucks London Fog | Sunkist Zero Sugar | |
|---|---|---|
| Caffeine per serving | 40mg per 16 oz grande (40mg at every size) | 19mg per 12 oz can |
| Caffeine per fl oz | 2.5mg | 1.6mg |
| Servings to reach 400mg (FDA context) | 10.0 | 21.1 |
Sources: Starbucks London Fog's figure is verified in our Starbucks London Fog caffeine guide against Starbucks nutrition listing (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 Starbucks London Fog 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
- Starbucks London Fog: the full caffeine guide
- Sunkist Zero Sugar: the full caffeine guide
- The verified caffeine database
FAQ
Does Starbucks London Fog or Sunkist Zero Sugar have more caffeine? Starbucks London Fog: 40mg per 16 oz grande (40mg at every size) versus 19mg per 12 oz can for Sunkist Zero Sugar.
Which is stronger per ounce? Starbucks London Fog, at about 2.5mg 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.