ZOA has more caffeine than Starbucks London Fog on both counts: 160mg per 12 oz can against 40mg per 16 oz grande (40mg at every size), and about 13mg 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.
ZOA vs Starbucks London Fog: the numbers
| ZOA | Starbucks London Fog | |
|---|---|---|
| Caffeine per serving | 160mg per 12 oz can | 40mg per 16 oz grande (40mg at every size) |
| Caffeine per fl oz | 13.3mg | 2.5mg |
| Servings to reach 400mg (FDA context) | 2.5 | 10.0 |
Sources: ZOA's figure is verified in our ZOA caffeine guide against ZOA FAQ (source); Starbucks London Fog's figure is verified in our Starbucks London Fog guide against Starbucks nutrition listing (source).
The concentration gap is the striking part: ZOA packs roughly 5 times the caffeine per ounce. Sipping speed matters at that density; a 12 oz can finished in minutes hits differently than the same milligrams spread over a slow cup.
Which one should you pick?
Pick Starbucks London Fog when you want the lighter dose or a slower ramp, and ZOA 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
- ZOA: the full caffeine guide
- Starbucks London Fog: the full caffeine guide
- The verified caffeine database
FAQ
Does ZOA or Starbucks London Fog have more caffeine? ZOA: 160mg per 12 oz can versus 40mg per 16 oz grande (40mg at every size) for Starbucks London Fog.
Which is stronger per ounce? ZOA, at about 13.3mg per fluid ounce versus 2.5mg for Starbucks London Fog.
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.